21015112220 has 48 divisors (see below), whose sum is σ = 45183186048. Its totient is φ = 8205986880.

The previous prime is 21015112219. The next prime is 21015112253. The reversal of 21015112220 is 2221151012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1826927 + ... + 1838393.

It is an arithmetic number, because the mean of its divisors is an integer number (941316376).

Almost surely, 2^21015112220 is an apocalyptic number.

21015112220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21015112220 is an abundant number, since it is smaller than the sum of its proper divisors (24168073828).

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

21015112220 is a wasteful number, since it uses less digits than its factorization.

21015112220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13650 (or 13648 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 17.

Adding to 21015112220 its reverse (2221151012), we get a palindrome (23236263232).

The spelling of 21015112220 in words is "twenty-one billion, fifteen million, one hundred twelve thousand, two hundred twenty".