21131646744 has 64 divisors (see below), whose sum is σ = 58728176640. Its totient is φ = 6292298880.

The previous prime is 21131646743. The next prime is 21131646751. The reversal of 21131646744 is 44764613112.

It is a super-2 number, since 2×21131646744² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131646743) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1082742 + ... + 1102085.

It is an arithmetic number, because the mean of its divisors is an integer number (917627760).

Almost surely, 2^21131646744 is an apocalyptic number.

21131646744 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21131646744 is an abundant number, since it is smaller than the sum of its proper divisors (37596529896).

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

21131646744 is a wasteful number, since it uses less digits than its factorization.

21131646744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2184880 (or 2184876 counting only the distinct ones).

The product of its digits is 96768, while the sum is 39.

The spelling of 21131646744 in words is "twenty-one billion, one hundred thirty-one million, six hundred forty-six thousand, seven hundred forty-four".