21629917680 has 320 divisors, whose sum is σ = 83270860800. Its totient is φ = 4532474880.

The previous prime is 21629917667. The next prime is 21629917709. The reversal of 21629917680 is 8671992612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 978591 + ... + 1000449.

It is an arithmetic number, because the mean of its divisors is an integer number (260221440).

Almost surely, 2^21629917680 is an apocalyptic number.

21629917680 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 21629917680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41635430400).

21629917680 is an abundant number, since it is smaller than the sum of its proper divisors (61640943120).

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

21629917680 is a wasteful number, since it uses less digits than its factorization.

21629917680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21932 (or 21926 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 51.

The spelling of 21629917680 in words is "twenty-one billion, six hundred twenty-nine million, nine hundred seventeen thousand, six hundred eighty".