21523321544 has 16 divisors (see below), whose sum is σ = 40363222320. Its totient is φ = 10759795600.

The previous prime is 21523321537. The next prime is 21523321549. The reversal of 21523321544 is 44512332512.

It is a self number, because there is not a number n which added to its sum of digits gives 21523321544.

It is not an unprimeable number, because it can be changed into a prime (21523321549) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 183482 + ... + 276969.

It is an arithmetic number, because the mean of its divisors is an integer number (2522701395).

Almost surely, 2^21523321544 is an apocalyptic number.

It is an amenable number.

21523321544 is a deficient number, since it is larger than the sum of its proper divisors (18839900776).

21523321544 is a wasteful number, since it uses less digits than its factorization.

21523321544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466300 (or 466296 counting only the distinct ones).

The product of its digits is 28800, while the sum is 32.

The spelling of 21523321544 in words is "twenty-one billion, five hundred twenty-three million, three hundred twenty-one thousand, five hundred forty-four".