21935979520 has 528 divisors, whose sum is σ = 68462815680. Its totient is φ = 6565920768.

The previous prime is 21935979509. The next prime is 21935979551. The reversal of 21935979520 is 2597953912.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 246471636 + ... + 246471724.

Almost surely, 2^21935979520 is an apocalyptic number.

21935979520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21935979520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34231407840).

21935979520 is an abundant number, since it is smaller than the sum of its proper divisors (46526836160).

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

21935979520 is a wasteful number, since it uses less digits than its factorization.

21935979520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180 (or 139 counting only the distinct ones).

The product of its (nonzero) digits is 1530900, while the sum is 52.

The spelling of 21935979520 in words is "twenty-one billion, nine hundred thirty-five million, nine hundred seventy-nine thousand, five hundred twenty".