21812370 has 16 divisors (see below), whose sum is σ = 52349760. Its totient is φ = 5816624.

The previous prime is 21812353. The next prime is 21812381. The reversal of 21812370 is 7321812.

It is a self number, because there is not a number n which added to its sum of digits gives 21812370.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 363510 + ... + 363569.

It is an arithmetic number, because the mean of its divisors is an integer number (3271860).

Almost surely, 2^21812370 is an apocalyptic number.

21812370 is an abundant number, since it is smaller than the sum of its proper divisors (30537390).

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

21812370 is a wasteful number, since it uses less digits than its factorization.

21812370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 727089.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21812370 is about 4670.3715055657. The cubic root of 21812370 is about 279.4050718597.

The spelling of 21812370 in words is "twenty-one million, eight hundred twelve thousand, three hundred seventy".