21820374 has 16 divisors (see below), whose sum is σ = 48489840. Its totient is φ = 7273440.

The previous prime is 21820349. The next prime is 21820391. The reversal of 21820374 is 47302812.

It is a super-2 number, since 2×21820374² = 952257442999752, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 201987 + ... + 202094.

It is an arithmetic number, because the mean of its divisors is an integer number (3030615).

Almost surely, 2^21820374 is an apocalyptic number.

21820374 is an abundant number, since it is smaller than the sum of its proper divisors (26669466).

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

21820374 is a wasteful number, since it uses less digits than its factorization.

21820374 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 404092 (or 404086 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 21820374 is about 4671.2283181193. The cubic root of 21820374 is about 279.4392433674.

The spelling of 21820374 in words is "twenty-one million, eight hundred twenty thousand, three hundred seventy-four".