21957002657 has 8 divisors (see below), whose sum is σ = 22391812584. Its totient is φ = 21522953088.

The previous prime is 21957002621. The next prime is 21957002659. The reversal of 21957002657 is 75620075912.

It can be written as a sum of positive squares in 4 ways, for example, as 17839342096 + 4117660561 = 133564^2 + 64169^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21957002657 - 2¹⁴ = 21956986273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21957002659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 131588 + ... + 247445.

It is an arithmetic number, because the mean of its divisors is an integer number (2798976573).

Almost surely, 2^21957002657 is an apocalyptic number.

It is an amenable number.

21957002657 is a deficient number, since it is larger than the sum of its proper divisors (434809927).

21957002657 is a wasteful number, since it uses less digits than its factorization.

21957002657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380179.

The product of its (nonzero) digits is 264600, while the sum is 44.

The spelling of 21957002657 in words is "twenty-one billion, nine hundred fifty-seven million, two thousand, six hundred fifty-seven".