21525431020 has 96 divisors (see below), whose sum is σ = 46453176000. Its totient is φ = 8376582144.

The previous prime is 21525430987. The next prime is 21525431111. The reversal of 21525431020 is 2013452512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 32663451 + ... + 32664109.

It is an arithmetic number, because the mean of its divisors is an integer number (483887250).

Almost surely, 2^21525431020 is an apocalyptic number.

21525431020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21525431020 is an abundant number, since it is smaller than the sum of its proper divisors (24927744980).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21525431020 is a wasteful number, since it uses less digits than its factorization.

21525431020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1027 (or 1025 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

Adding to 21525431020 its reverse (2013452512), we get a palindrome (23538883532).

The spelling of 21525431020 in words is "twenty-one billion, five hundred twenty-five million, four hundred thirty-one thousand, twenty".