21122957568 has 144 divisors (see below), whose sum is σ = 58344720896. Its totient is φ = 6777077760.

The previous prime is 21122957561. The next prime is 21122957579. The reversal of 21122957568 is 86575922112.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (21122957561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4592646 + ... + 4597242.

Almost surely, 2^21122957568 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21122957568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29172360448).

21122957568 is an abundant number, since it is smaller than the sum of its proper divisors (37221763328).

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

21122957568 is a wasteful number, since it uses less digits than its factorization.

21122957568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4840 (or 4826 counting only the distinct ones).

The product of its digits is 604800, while the sum is 48.

The spelling of 21122957568 in words is "twenty-one billion, one hundred twenty-two million, nine hundred fifty-seven thousand, five hundred sixty-eight".