21444400131 has 128 divisors (see below), whose sum is σ = 37407744000. Its totient is φ = 10828702080.

The previous prime is 21444400111. The next prime is 21444400193. The reversal of 21444400131 is 13100444412.

It is not a de Polignac number, because 21444400131 - 2¹⁰ = 21444399107 is a prime.

It is a super-2 number, since 2×21444400131² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21444400111) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 108854725 + ... + 108854921.

It is an arithmetic number, because the mean of its divisors is an integer number (292248000).

Almost surely, 2^21444400131 is an apocalyptic number.

21444400131 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21444400131 is a deficient number, since it is larger than the sum of its proper divisors (15963343869).

21444400131 is a wasteful number, since it uses less digits than its factorization.

21444400131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454 (or 440 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 21444400131 its reverse (13100444412), we get a palindrome (34544844543).

The spelling of 21444400131 in words is "twenty-one billion, four hundred forty-four million, four hundred thousand, one hundred thirty-one".