21573642318 has 64 divisors (see below), whose sum is σ = 45543532608. Its totient is φ = 6803758080.

The previous prime is 21573642317. The next prime is 21573642361. The reversal of 21573642318 is 81324637512.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21573642318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21573642317) 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, 2881596 + ... + 2889072.

It is an arithmetic number, because the mean of its divisors is an integer number (711617697).

Almost surely, 2^21573642318 is an apocalyptic number.

21573642318 is an abundant number, since it is smaller than the sum of its proper divisors (23969890290).

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

21573642318 is a wasteful number, since it uses less digits than its factorization.

21573642318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7877.

The product of its digits is 241920, while the sum is 42.

The spelling of 21573642318 in words is "twenty-one billion, five hundred seventy-three million, six hundred forty-two thousand, three hundred eighteen".