56999666655566 has 4 divisors (see below), whose sum is σ = 85499499983352. Its totient is φ = 28499833327782.

The previous prime is 56999666655553. The next prime is 56999666655571. The reversal of 56999666655566 is 66555666699965.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14249916663890 + ... + 14249916663893.

It is an arithmetic number, because the mean of its divisors is an integer number (21374874995838).

Almost surely, 2^{56999666655566} is an apocalyptic number.

56999666655566 is a deficient number, since it is larger than the sum of its proper divisors (28499833327786).

56999666655566 is a wasteful number, since it uses less digits than its factorization.

56999666655566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28499833327785.

The product of its digits is 127545840000, while the sum is 89.

The spelling of 56999666655566 in words is "fifty-six trillion, nine hundred ninety-nine billion, six hundred sixty-six million, six hundred fifty-five thousand, five hundred sixty-six".