21660973544 has 32 divisors (see below), whose sum is σ = 46463047680. Its totient is φ = 9273939264.

The previous prime is 21660973513. The next prime is 21660973549. The reversal of 21660973544 is 44537906612.

It is not an unprimeable number, because it can be changed into a prime (21660973549) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 138152 + ... + 249815.

It is an arithmetic number, because the mean of its divisors is an integer number (1451970240).

Almost surely, 2^21660973544 is an apocalyptic number.

It is an amenable number.

21660973544 is an abundant number, since it is smaller than the sum of its proper divisors (24802074136).

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

21660973544 is a wasteful number, since it uses less digits than its factorization.

21660973544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 388977 (or 388973 counting only the distinct ones).

The product of its (nonzero) digits is 1088640, while the sum is 47.

The spelling of 21660973544 in words is "twenty-one billion, six hundred sixty million, nine hundred seventy-three thousand, five hundred forty-four".