21890372 has 12 divisors (see below), whose sum is σ = 43780800. Its totient is φ = 9381576.

The previous prime is 21890369. The next prime is 21890377. The reversal of 21890372 is 27309812.

21890372 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21890377) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 390872 + ... + 390927.

It is an arithmetic number, because the mean of its divisors is an integer number (3648400).

Almost surely, 2^21890372 is an apocalyptic number.

It is an amenable number.

21890372 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21890372 is a wasteful number, since it uses less digits than its factorization.

21890372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 781810 (or 781808 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 21890372 is about 4678.7147807918. The cubic root of 21890372 is about 279.7377306056.

The spelling of 21890372 in words is "twenty-one million, eight hundred ninety thousand, three hundred seventy-two".