21913620 has 48 divisors (see below), whose sum is σ = 63022848. Its totient is φ = 5685120.

The previous prime is 21913601. The next prime is 21913627. The reversal of 21913620 is 2631912.

21913620 = 248² + 249² + ... + 432².

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21913627) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2716 + ... + 7155.

It is an arithmetic number, because the mean of its divisors is an integer number (1312976).

Almost surely, 2^21913620 is an apocalyptic number.

21913620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21913620 is an abundant number, since it is smaller than the sum of its proper divisors (41109228).

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

21913620 is a wasteful number, since it uses less digits than its factorization.

21913620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9920 (or 9918 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 21913620 is about 4681.1985644704. The cubic root of 21913620 is about 279.8367245361.

The spelling of 21913620 in words is "twenty-one million, nine hundred thirteen thousand, six hundred twenty".