21515536220 has 24 divisors (see below), whose sum is σ = 45319143408. Its totient is φ = 8580211200.

The previous prime is 21515536199. The next prime is 21515536291. The reversal of 21515536220 is 2263551512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1618421 + ... + 1631660.

It is an arithmetic number, because the mean of its divisors is an integer number (1888297642).

Almost surely, 2^21515536220 is an apocalyptic number.

21515536220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21515536220 is an abundant number, since it is smaller than the sum of its proper divisors (23803607188).

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

21515536220 is a wasteful number, since it uses less digits than its factorization.

21515536220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3250421 (or 3250419 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 32.

The spelling of 21515536220 in words is "twenty-one billion, five hundred fifteen million, five hundred thirty-six thousand, two hundred twenty".