21525512531 has 2 divisors, whose sum is σ = 21525512532. Its totient is φ = 21525512530.

The previous prime is 21525512521. The next prime is 21525512539. The reversal of 21525512531 is 13521552512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21525512531 - 2³⁰ = 20451770707 is a prime.

It is a super-2 number, since 2×21525512531² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21525512539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10762756265 + 10762756266.

It is an arithmetic number, because the mean of its divisors is an integer number (10762756266).

Almost surely, 2^21525512531 is an apocalyptic number.

21525512531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21525512531 is an equidigital number, since it uses as much as digits as its factorization.

21525512531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15000, while the sum is 32.

The spelling of 21525512531 in words is "twenty-one billion, five hundred twenty-five million, five hundred twelve thousand, five hundred thirty-one".