21518596680 has 768 divisors, whose sum is σ = 85108838400. Its totient is φ = 4242585600.

The previous prime is 21518596633. The next prime is 21518596739. The reversal of 21518596680 is 8669581512.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 352763850 + ... + 352763910.

It is an arithmetic number, because the mean of its divisors is an integer number (110818800).

Almost surely, 2^21518596680 is an apocalyptic number.

21518596680 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 21518596680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42554419200).

21518596680 is an abundant number, since it is smaller than the sum of its proper divisors (63590241720).

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

21518596680 is a wasteful number, since it uses less digits than its factorization.

21518596680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186 (or 151 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 51.

The spelling of 21518596680 in words is "twenty-one billion, five hundred eighteen million, five hundred ninety-six thousand, six hundred eighty".