21621361544623 has 12 divisors (see below), whose sum is σ = 22349942225184. Its totient is φ = 20915826480000.

The previous prime is 21621361544609. The next prime is 21621361544683. The reversal of 21621361544623 is 32644516312612.

It is not a de Polignac number, because 21621361544623 - 2¹³ = 21621361536431 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621361544683) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1846503 + ... + 6830248.

It is an arithmetic number, because the mean of its divisors is an integer number (1862495185432).

Almost surely, 2^{21621361544623} is an apocalyptic number.

21621361544623 is a deficient number, since it is larger than the sum of its proper divisors (728580680561).

21621361544623 is an equidigital number, since it uses as much as digits as its factorization.

21621361544623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8679406 (or 8679375 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 46.

The spelling of 21621361544623 in words is "twenty-one trillion, six hundred twenty-one billion, three hundred sixty-one million, five hundred forty-four thousand, six hundred twenty-three".