21583715621 has 8 divisors (see below), whose sum is σ = 23993808384. Its totient is φ = 19280738160.

The previous prime is 21583715599. The next prime is 21583715623. The reversal of 21583715621 is 12651738512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21583715621 - 2¹⁰ = 21583714597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21583715623) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26778401 + ... + 26779206.

It is an arithmetic number, because the mean of its divisors is an integer number (2999226048).

Almost surely, 2^21583715621 is an apocalyptic number.

It is an amenable number.

21583715621 is a deficient number, since it is larger than the sum of its proper divisors (2410092763).

21583715621 is a wasteful number, since it uses less digits than its factorization.

21583715621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53557651.

The product of its digits is 100800, while the sum is 41.

The spelling of 21583715621 in words is "twenty-one billion, five hundred eighty-three million, seven hundred fifteen thousand, six hundred twenty-one".