21739039257 has 16 divisors (see below), whose sum is σ = 31406543168. Its totient is φ = 13295793600.

The previous prime is 21739039177. The next prime is 21739039271. The reversal of 21739039257 is 75293093712.

It is not a de Polignac number, because 21739039257 - 2⁸ = 21739039001 is a prime.

It is a super-2 number, since 2×21739039257² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21739039457) 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, 1703494 + ... + 1716207.

It is an arithmetic number, because the mean of its divisors is an integer number (1962908948).

Almost surely, 2^21739039257 is an apocalyptic number.

It is an amenable number.

21739039257 is a deficient number, since it is larger than the sum of its proper divisors (9667503911).

21739039257 is a wasteful number, since it uses less digits than its factorization.

21739039257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3419880.

The product of its (nonzero) digits is 714420, while the sum is 48.

The spelling of 21739039257 in words is "twenty-one billion, seven hundred thirty-nine million, thirty-nine thousand, two hundred fifty-seven".