21131222120 has 16 divisors (see below), whose sum is σ = 47545249860. Its totient is φ = 8452488832.

The previous prime is 21131222111. The next prime is 21131222129. The reversal of 21131222120 is 2122213112.

It is an interprime number because it is at equal distance from previous prime (21131222111) and next prime (21131222129).

It can be written as a sum of positive squares in 2 ways, for example, as 19873668676 + 1257553444 = 140974^2 + 35462^2 .

It is not an unprimeable number, because it can be changed into a prime (21131222129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 264140237 + ... + 264140316.

Almost surely, 2^21131222120 is an apocalyptic number.

21131222120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21131222120 is an abundant number, since it is smaller than the sum of its proper divisors (26414027740).

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

21131222120 is a wasteful number, since it uses less digits than its factorization.

21131222120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528280564 (or 528280560 counting only the distinct ones).

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

Adding to 21131222120 its reverse (2122213112), we get a palindrome (23253435232).

The spelling of 21131222120 in words is "twenty-one billion, one hundred thirty-one million, two hundred twenty-two thousand, one hundred twenty".