21365025472557 has 12 divisors (see below), whose sum is σ = 33234484068604. Its totient is φ = 13147707983040.

The previous prime is 21365025472493. The next prime is 21365025472577. The reversal of 21365025472557 is 75527452056312.

21365025472557 is a `hidden beast` number, since 2 + 1 + 3 + 65 + 0 + 25 + 4 + 7 + 2 + 557 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 12089675034441 + 9275350438116 = 3477021^2 + 3045546^2 .

It is not a de Polignac number, because 21365025472557 - 2⁶ = 21365025472493 is a prime.

It is a super-2 number, since 2×21365025472557² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21365025472577) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 91303527544 + ... + 91303527777.

Almost surely, 2^{21365025472557} is an apocalyptic number.

It is an amenable number.

21365025472557 is a deficient number, since it is larger than the sum of its proper divisors (11869458596047).

21365025472557 is a wasteful number, since it uses less digits than its factorization.

21365025472557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182607055340 (or 182607055337 counting only the distinct ones).

The product of its (nonzero) digits is 17640000, while the sum is 54.

The spelling of 21365025472557 in words is "twenty-one trillion, three hundred sixty-five billion, twenty-five million, four hundred seventy-two thousand, five hundred fifty-seven".