21373720 has 32 divisors (see below), whose sum is σ = 49118400. Its totient is φ = 8366848.

The previous prime is 21373717. The next prime is 21373771. The reversal of 21373720 is 2737312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3805 + ... + 7564.

It is an arithmetic number, because the mean of its divisors is an integer number (1534950).

Almost surely, 2^21373720 is an apocalyptic number.

21373720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21373720 is an abundant number, since it is smaller than the sum of its proper divisors (27744680).

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

21373720 is a wasteful number, since it uses less digits than its factorization.

21373720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11427 (or 11423 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 25.

The square root of 21373720 is about 4623.1720712083. The cubic root of 21373720 is about 277.5194153556.

The spelling of 21373720 in words is "twenty-one million, three hundred seventy-three thousand, seven hundred twenty".