21657122608 has 20 divisors (see below), whose sum is σ = 45775282248. Its totient is φ = 9844146560.

The previous prime is 21657122581. The next prime is 21657122609. The reversal of 21657122608 is 80622175612.

It is not an unprimeable number, because it can be changed into a prime (21657122609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61525741 + ... + 61526092.

Almost surely, 2^21657122608 is an apocalyptic number.

It is an amenable number.

21657122608 is an abundant number, since it is smaller than the sum of its proper divisors (24118159640).

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

21657122608 is a wasteful number, since it uses less digits than its factorization.

21657122608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123051852 (or 123051846 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 40.

The spelling of 21657122608 in words is "twenty-one billion, six hundred fifty-seven million, one hundred twenty-two thousand, six hundred eight".