21593924257 has 4 divisors (see below), whose sum is σ = 21595121856. Its totient is φ = 21592726660.

The previous prime is 21593924237. The next prime is 21593924281. The reversal of 21593924257 is 75242939512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21593924257 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21593924257.

It is not an unprimeable number, because it can be changed into a prime (21593924207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 571333 + ... + 607954.

It is an arithmetic number, because the mean of its divisors is an integer number (5398780464).

Almost surely, 2^21593924257 is an apocalyptic number.

It is an amenable number.

21593924257 is a deficient number, since it is larger than the sum of its proper divisors (1197599).

21593924257 is a wasteful number, since it uses less digits than its factorization.

21593924257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1197598.

The product of its digits is 1360800, while the sum is 49.

The spelling of 21593924257 in words is "twenty-one billion, five hundred ninety-three million, nine hundred twenty-four thousand, two hundred fifty-seven".