21192521531 has 2 divisors, whose sum is σ = 21192521532. Its totient is φ = 21192521530.

The previous prime is 21192521513. The next prime is 21192521621. The reversal of 21192521531 is 13512529112.

Together with previous prime (21192521513) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21192521531 - 2²⁶ = 21125412667 is a prime.

It is a super-2 number, since 2×21192521531² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21192521501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10596260765 + 10596260766.

It is an arithmetic number, because the mean of its divisors is an integer number (10596260766).

Almost surely, 2^21192521531 is an apocalyptic number.

21192521531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21192521531 is an equidigital number, since it uses as much as digits as its factorization.

21192521531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5400, while the sum is 32.

The spelling of 21192521531 in words is "twenty-one billion, one hundred ninety-two million, five hundred twenty-one thousand, five hundred thirty-one".