21680737344 has 280 divisors, whose sum is σ = 75822990848. Its totient is φ = 5994362880.

The previous prime is 21680737333. The next prime is 21680737363. The reversal of 21680737344 is 44373708612.

It is a self number, because there is not a number n which added to its sum of digits gives 21680737344.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1115292 + ... + 1134564.

Almost surely, 2^21680737344 is an apocalyptic number.

21680737344 is a gapful number since it is divisible by the number (24) 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 21680737344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37911495424).

21680737344 is an abundant number, since it is smaller than the sum of its proper divisors (54142253504).

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

21680737344 is a wasteful number, since it uses less digits than its factorization.

21680737344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19335 (or 19316 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 45.

The spelling of 21680737344 in words is "twenty-one billion, six hundred eighty million, seven hundred thirty-seven thousand, three hundred forty-four".