21252536531 has 4 divisors (see below), whose sum is σ = 21508591272. Its totient is φ = 20996481792.

The previous prime is 21252536527. The next prime is 21252536537. The reversal of 21252536531 is 13563525212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21252536531 - 2² = 21252536527 is a prime.

It is a super-2 number, since 2×21252536531² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21252536491 and 21252536500.

It is not an unprimeable number, because it can be changed into a prime (21252536537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128027246 + ... + 128027411.

It is an arithmetic number, because the mean of its divisors is an integer number (5377147818).

Almost surely, 2^21252536531 is an apocalyptic number.

21252536531 is a deficient number, since it is larger than the sum of its proper divisors (256054741).

21252536531 is an equidigital number, since it uses as much as digits as its factorization.

21252536531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256054740.

The product of its digits is 54000, while the sum is 35.

The spelling of 21252536531 in words is "twenty-one billion, two hundred fifty-two million, five hundred thirty-six thousand, five hundred thirty-one".