21623755642520 has 64 divisors (see below), whose sum is σ = 49193739201600. Its totient is φ = 8553655052800.

The previous prime is 21623755642519. The next prime is 21623755642553. The reversal of 21623755642520 is 2524655732612.

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, 199802 + ... + 6579318.

It is an arithmetic number, because the mean of its divisors is an integer number (768652175025).

Almost surely, 2^{21623755642520} is an apocalyptic number.

21623755642520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21623755642520 is an abundant number, since it is smaller than the sum of its proper divisors (27569983559080).

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

21623755642520 is a wasteful number, since it uses less digits than its factorization.

21623755642520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6380468 (or 6380464 counting only the distinct ones).

The product of its (nonzero) digits is 6048000, while the sum is 50.

The spelling of 21623755642520 in words is "twenty-one trillion, six hundred twenty-three billion, seven hundred fifty-five million, six hundred forty-two thousand, five hundred twenty".