21957476537 has 2 divisors, whose sum is σ = 21957476538. Its totient is φ = 21957476536.

The previous prime is 21957476509. The next prime is 21957476617. The reversal of 21957476537 is 73567475912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19242128656 + 2715347881 = 138716^2 + 52109^2 .

It is a cyclic number.

It is not a de Polignac number, because 21957476537 - 2⁶ = 21957476473 is a prime.

It is not a weakly prime, because it can be changed into another prime (11957476537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10978738268 + 10978738269.

It is an arithmetic number, because the mean of its divisors is an integer number (10978738269).

Almost surely, 2^21957476537 is an apocalyptic number.

It is an amenable number.

21957476537 is a deficient number, since it is larger than the sum of its proper divisors (1).

21957476537 is an equidigital number, since it uses as much as digits as its factorization.

21957476537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11113200, while the sum is 56.

The spelling of 21957476537 in words is "twenty-one billion, nine hundred fifty-seven million, four hundred seventy-six thousand, five hundred thirty-seven".