21131230220 has 24 divisors (see below), whose sum is σ = 46304957664. Its totient is φ = 8084992256.

The previous prime is 21131230177. The next prime is 21131230223. The reversal of 21131230220 is 2203213112.

It is a super-2 number, since 2×21131230220² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21131230223) 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 7 ways as a sum of consecutive naturals, for example, 22968269 + ... + 22969188.

It is an arithmetic number, because the mean of its divisors is an integer number (1929373236).

Almost surely, 2^21131230220 is an apocalyptic number.

21131230220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21131230220 is an abundant number, since it is smaller than the sum of its proper divisors (25173727444).

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

21131230220 is a wasteful number, since it uses less digits than its factorization.

21131230220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45937489 (or 45937487 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21131230220 its reverse (2203213112), we get a palindrome (23334443332).

The spelling of 21131230220 in words is "twenty-one billion, one hundred thirty-one million, two hundred thirty thousand, two hundred twenty".