21311222120 has 32 divisors (see below), whose sum is σ = 48198714120. Its totient is φ = 8480317440.

The previous prime is 21311222081. The next prime is 21311222129. The reversal of 21311222120 is 2122211312.

It can be written as a sum of positive squares in 4 ways, for example, as 20199799876 + 1111422244 = 142126^2 + 33338^2 .

It is not an unprimeable number, because it can be changed into a prime (21311222129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1372541 + ... + 1387980.

Almost surely, 2^21311222120 is an apocalyptic number.

21311222120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21311222120 is an abundant number, since it is smaller than the sum of its proper divisors (26887492000).

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

21311222120 is a wasteful number, since it uses less digits than its factorization.

21311222120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2760725 (or 2760721 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21311222120 its reverse (2122211312), we get a palindrome (23433433432).

The spelling of 21311222120 in words is "twenty-one billion, three hundred eleven million, two hundred twenty-two thousand, one hundred twenty".