21013041220 has 12 divisors (see below), whose sum is σ = 44127386604. Its totient is φ = 8405216480.

The previous prime is 21013041191. The next prime is 21013041349. The reversal of 21013041220 is 2214031012.

It can be written as a sum of positive squares in 2 ways, for example, as 4791962176 + 16221079044 = 69224^2 + 127362^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21013041194 and 21013041203.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525326011 + ... + 525326050.

It is an arithmetic number, because the mean of its divisors is an integer number (3677282217).

Almost surely, 2^21013041220 is an apocalyptic number.

21013041220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21013041220 is an abundant number, since it is smaller than the sum of its proper divisors (23114345384).

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

21013041220 is a wasteful number, since it uses less digits than its factorization.

21013041220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1050652070 (or 1050652068 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21013041220 its reverse (2214031012), we get a palindrome (23227072232).

The spelling of 21013041220 in words is "twenty-one billion, thirteen million, forty-one thousand, two hundred twenty".