21621337721574 has 32 divisors (see below), whose sum is σ = 43577480732544. Its totient is φ = 7151323583040.

The previous prime is 21621337721549. The next prime is 21621337721623. The reversal of 21621337721574 is 47512773312612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5814802 + ... + 8778074.

It is an arithmetic number, because the mean of its divisors is an integer number (1361796272892).

Almost surely, 2^{21621337721574} is an apocalyptic number.

21621337721574 is an abundant number, since it is smaller than the sum of its proper divisors (21956143010970).

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

21621337721574 is a wasteful number, since it uses less digits than its factorization.

21621337721574 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2972692.

The product of its digits is 2963520, while the sum is 51.

The spelling of 21621337721574 in words is "twenty-one trillion, six hundred twenty-one billion, three hundred thirty-seven million, seven hundred twenty-one thousand, five hundred seventy-four".