21957131713 has 4 divisors (see below), whose sum is σ = 23953234608. Its totient is φ = 19961028820.

The previous prime is 21957131699. The next prime is 21957131809. The reversal of 21957131713 is 31713175912.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21957131713 - 2⁵ = 21957131681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21957131113) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 998051431 + ... + 998051452.

It is an arithmetic number, because the mean of its divisors is an integer number (5988308652).

Almost surely, 2^21957131713 is an apocalyptic number.

It is an amenable number.

21957131713 is a deficient number, since it is larger than the sum of its proper divisors (1996102895).

21957131713 is a wasteful number, since it uses less digits than its factorization.

21957131713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1996102894.

The product of its digits is 39690, while the sum is 40.

The spelling of 21957131713 in words is "twenty-one billion, nine hundred fifty-seven million, one hundred thirty-one thousand, seven hundred thirteen".