21513298723 has 32 divisors (see below), whose sum is σ = 26385408000. Its totient is φ = 17149466880.

The previous prime is 21513298661. The next prime is 21513298747. The reversal of 21513298723 is 32789231512.

It is not a de Polignac number, because 21513298723 - 2²¹ = 21511201571 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21513298723.

It is not an unprimeable number, because it can be changed into a prime (21513298753) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 641158 + ... + 673876.

It is an arithmetic number, because the mean of its divisors is an integer number (824544000).

Almost surely, 2^21513298723 is an apocalyptic number.

21513298723 is a deficient number, since it is larger than the sum of its proper divisors (4872109277).

21513298723 is a wasteful number, since it uses less digits than its factorization.

21513298723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32875.

The product of its digits is 181440, while the sum is 43.

The spelling of 21513298723 in words is "twenty-one billion, five hundred thirteen million, two hundred ninety-eight thousand, seven hundred twenty-three".