21521125053 has 6 divisors (see below), whose sum is σ = 31086069534. Its totient is φ = 14347416696.

The previous prime is 21521125033. The next prime is 21521125063. The reversal of 21521125053 is 35052112512.

21521125053 is a `hidden beast` number, since 2 + 152 + 1 + 1 + 2 + 505 + 3 = 666.

It can be written as a sum of positive squares in only one way, i.e., 12913367769 + 8607757284 = 113637^2 + 92778^2 .

It is not a de Polignac number, because 21521125053 - 2⁸ = 21521124797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521125033) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1195618050 + ... + 1195618067.

It is an arithmetic number, because the mean of its divisors is an integer number (5181011589).

Almost surely, 2^21521125053 is an apocalyptic number.

It is an amenable number.

21521125053 is a deficient number, since it is larger than the sum of its proper divisors (9564944481).

21521125053 is a wasteful number, since it uses less digits than its factorization.

21521125053 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2391236123 (or 2391236120 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

Adding to 21521125053 its reverse (35052112512), we get a palindrome (56573237565).

The spelling of 21521125053 in words is "twenty-one billion, five hundred twenty-one million, one hundred twenty-five thousand, fifty-three".