21620480 has 144 divisors (see below), whose sum is σ = 62791680. Its totient is φ = 6967296.

The previous prime is 21620479. The next prime is 21620497. The reversal of 21620480 is 8402612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 170177 + ... + 170303.

Almost surely, 2^21620480 is an apocalyptic number.

21620480 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 21620480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31395840).

21620480 is an abundant number, since it is smaller than the sum of its proper divisors (41171200).

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

21620480 is a wasteful number, since it uses less digits than its factorization.

21620480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174 (or 160 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 21620480 is about 4649.7827906258. The cubic root of 21620480 is about 278.5833204904.

The spelling of 21620480 in words is "twenty-one million, six hundred twenty thousand, four hundred eighty".