21557677772 has 6 divisors (see below), whose sum is σ = 37725936108. Its totient is φ = 10778838884.

The previous prime is 21557677753. The next prime is 21557677777. The reversal of 21557677772 is 27777675512.

It is not an unprimeable number, because it can be changed into a prime (21557677777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2694709718 + ... + 2694709725.

It is an arithmetic number, because the mean of its divisors is an integer number (6287656018).

Almost surely, 2^21557677772 is an apocalyptic number.

It is an amenable number.

21557677772 is a deficient number, since it is larger than the sum of its proper divisors (16168258336).

21557677772 is a wasteful number, since it uses less digits than its factorization.

21557677772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5389419447 (or 5389419445 counting only the distinct ones).

The product of its digits is 10084200, while the sum is 56.

The spelling of 21557677772 in words is "twenty-one billion, five hundred fifty-seven million, six hundred seventy-seven thousand, seven hundred seventy-two".