21524532421 has 4 divisors (see below), whose sum is σ = 24599465632. Its totient is φ = 18449599212.

The previous prime is 21524532383. The next prime is 21524532461. The reversal of 21524532421 is 12423542512.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21524532421 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21524532461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1537466595 + ... + 1537466608.

It is an arithmetic number, because the mean of its divisors is an integer number (6149866408).

Almost surely, 2^21524532421 is an apocalyptic number.

It is an amenable number.

21524532421 is a deficient number, since it is larger than the sum of its proper divisors (3074933211).

21524532421 is an equidigital number, since it uses as much as digits as its factorization.

21524532421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3074933210.

The product of its digits is 19200, while the sum is 31.

The spelling of 21524532421 in words is "twenty-one billion, five hundred twenty-four million, five hundred thirty-two thousand, four hundred twenty-one".