21617157057 has 16 divisors (see below), whose sum is σ = 29802393600. Its totient is φ = 13923234000.

The previous prime is 21617157031. The next prime is 21617157073. The reversal of 21617157057 is 75075171612.

It is not a de Polignac number, because 21617157057 - 2¹⁵ = 21617124289 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21617157097) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 138319 + ... + 249732.

It is an arithmetic number, because the mean of its divisors is an integer number (1862649600).

Almost surely, 2^21617157057 is an apocalyptic number.

It is an amenable number.

21617157057 is a deficient number, since it is larger than the sum of its proper divisors (8185236543).

21617157057 is a wasteful number, since it uses less digits than its factorization.

21617157057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388684.

The product of its (nonzero) digits is 102900, while the sum is 42.

The spelling of 21617157057 in words is "twenty-one billion, six hundred seventeen million, one hundred fifty-seven thousand, fifty-seven".