21131213344 has 24 divisors (see below), whose sum is σ = 41970243420. Its totient is φ = 10472103936.

The previous prime is 21131213329. The next prime is 21131213359. The reversal of 21131213344 is 44331213112.

It is an interprime number because it is at equal distance from previous prime (21131213329) and next prime (21131213359).

It can be written as a sum of positive squares in 2 ways, for example, as 16278697744 + 4852515600 = 127588^2 + 69660^2 .

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, 2918289 + ... + 2925520.

Almost surely, 2^21131213344 is an apocalyptic number.

It is an amenable number.

21131213344 is a deficient number, since it is larger than the sum of its proper divisors (20839030076).

21131213344 is a wasteful number, since it uses less digits than its factorization.

21131213344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5843932 (or 5843924 counting only the distinct ones).

The product of its digits is 1728, while the sum is 25.

Adding to 21131213344 its reverse (44331213112), we get a palindrome (65462426456).

The spelling of 21131213344 in words is "twenty-one billion, one hundred thirty-one million, two hundred thirteen thousand, three hundred forty-four".