21165702057 has 32 divisors (see below), whose sum is σ = 32022950400. Its totient is φ = 13811855616.

The previous prime is 21165702043. The next prime is 21165702071. The reversal of 21165702057 is 75020756112.

21165702057 is a `hidden beast` number, since 2 + 1 + 16 + 570 + 20 + 57 = 666.

It is an interprime number because it is at equal distance from previous prime (21165702043) and next prime (21165702071).

It is not a de Polignac number, because 21165702057 - 2⁷ = 21165701929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21165702007) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 602544 + ... + 636702.

It is an arithmetic number, because the mean of its divisors is an integer number (1000717200).

Almost surely, 2^21165702057 is an apocalyptic number.

21165702057 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21165702057 is a deficient number, since it is larger than the sum of its proper divisors (10857248343).

21165702057 is a wasteful number, since it uses less digits than its factorization.

21165702057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34654 (or 34648 counting only the distinct ones).

The product of its (nonzero) digits is 29400, while the sum is 36.

The spelling of 21165702057 in words is "twenty-one billion, one hundred sixty-five million, seven hundred two thousand, fifty-seven".