21631354520 has 32 divisors (see below), whose sum is σ = 48682468800. Its totient is φ = 8650422528.

The previous prime is 21631354471. The next prime is 21631354531. The reversal of 21631354520 is 2545313612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 104561 + ... + 232799.

It is an arithmetic number, because the mean of its divisors is an integer number (1521327150).

Almost surely, 2^21631354520 is an apocalyptic number.

21631354520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21631354520 is an abundant number, since it is smaller than the sum of its proper divisors (27051114280).

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

21631354520 is a wasteful number, since it uses less digits than its factorization.

21631354520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132467 (or 132463 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 32.

The spelling of 21631354520 in words is "twenty-one billion, six hundred thirty-one million, three hundred fifty-four thousand, five hundred twenty".