21657621522 has 8 divisors (see below), whose sum is σ = 43315243056. Its totient is φ = 7219207172.

The previous prime is 21657621499. The next prime is 21657621571. The reversal of 21657621522 is 22512675612.

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

21657621522 is an admirable number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1804801788 + ... + 1804801799.

It is an arithmetic number, because the mean of its divisors is an integer number (5414405382).

Almost surely, 2^21657621522 is an apocalyptic number.

21657621522 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21657621522 is a wasteful number, since it uses less digits than its factorization.

21657621522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3609603592.

The product of its digits is 100800, while the sum is 39.

The spelling of 21657621522 in words is "twenty-one billion, six hundred fifty-seven million, six hundred twenty-one thousand, five hundred twenty-two".