21013001220 has 24 divisors (see below), whose sum is σ = 58836403584. Its totient is φ = 5603466976.

The previous prime is 21013001201. The next prime is 21013001231. The reversal of 21013001220 is 2210031012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21013001196 and 21013001205.

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, 175108284 + ... + 175108403.

It is an arithmetic number, because the mean of its divisors is an integer number (2451516816).

Almost surely, 2^21013001220 is an apocalyptic number.

21013001220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21013001220 is an abundant number, since it is smaller than the sum of its proper divisors (37823402364).

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

21013001220 is a wasteful number, since it uses less digits than its factorization.

21013001220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350216699 (or 350216697 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21013001220 its reverse (2210031012), we get a palindrome (23223032232).

The spelling of 21013001220 in words is "twenty-one billion, thirteen million, one thousand, two hundred twenty".