21573443418 has 32 divisors (see below), whose sum is σ = 44642741760. Its totient is φ = 6941928000.

The previous prime is 21573443413. The next prime is 21573443453. The reversal of 21573443418 is 81434437512.

It is a self number, because there is not a number n which added to its sum of digits gives 21573443418.

It is not an unprimeable number, because it can be changed into a prime (21573443413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1821271 + ... + 1833077.

It is an arithmetic number, because the mean of its divisors is an integer number (1395085680).

Almost surely, 2^21573443418 is an apocalyptic number.

21573443418 is an abundant number, since it is smaller than the sum of its proper divisors (23069298342).

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

21573443418 is a wasteful number, since it uses less digits than its factorization.

21573443418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22342.

The product of its digits is 322560, while the sum is 42.

The spelling of 21573443418 in words is "twenty-one billion, five hundred seventy-three million, four hundred forty-three thousand, four hundred eighteen".