What is the meaning of the values of the Protocols field from Get-TlsCipherSuite Output?

They seem to be a decimal representation of the value used in the TLS Version Field. 771 = 0x0303 = TLS_1_2, and 652677 = 0xFEFD = DTLS_1_1. You can see similar constants defined in various TLS libraries:

TLS_VERSIONS = {
    # SSL
    0x0002: "SSL_2_0",
    0x0300: "SSL_3_0",
    # TLS:
    0x0301: "TLS_1_0",
    0x0302: "TLS_1_1",
    0x0303: "TLS_1_2",
    0x0304: "TLS_1_3",
    # DTLS
    0x0100: "PROTOCOL_DTLS_1_0_OPENSSL_PRE_0_9_8f",
    0x7f10: "TLS_1_3_DRAFT_16",
    0x7f12: "TLS_1_3_DRAFT_18",
    0xfeff: "DTLS_1_0",
    0xfefd: "DTLS_1_1",
}

So they likely represent the TLS/SSL protocol versions for which that cipher is available.