21075732444 has 72 divisors (see below), whose sum is σ = 56053280640. Its totient is φ = 6143522112.

The previous prime is 21075732413. The next prime is 21075732449. The reversal of 21075732444 is 44423757012.

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 (21075732449) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 234952 + ... + 312015.

Almost surely, 2^21075732444 is an apocalyptic number.

It is an amenable number.

21075732444 is an abundant number, since it is smaller than the sum of its proper divisors (34977548196).

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

21075732444 is a wasteful number, since it uses less digits than its factorization.

21075732444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 547019 (or 547004 counting only the distinct ones).

The product of its (nonzero) digits is 188160, while the sum is 39.

The spelling of 21075732444 in words is "twenty-one billion, seventy-five million, seven hundred thirty-two thousand, four hundred forty-four".