21990375 has 48 divisors (see below), whose sum is σ = 43269408. Its totient is φ = 10656000.

The previous prime is 21990373. The next prime is 21990413. The reversal of 21990375 is 57309912.

It is not a de Polignac number, because 21990375 - 2¹ = 21990373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21990373) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11487 + ... + 13263.

It is an arithmetic number, because the mean of its divisors is an integer number (901446).

Almost surely, 2^21990375 is an apocalyptic number.

21990375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21990375 is a deficient number, since it is larger than the sum of its proper divisors (21279033).

21990375 is a wasteful number, since it uses less digits than its factorization.

21990375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1809 (or 1796 counting only the distinct ones).

The product of its (nonzero) digits is 17010, while the sum is 36.

The square root of 21990375 is about 4689.3896191296. The cubic root of 21990375 is about 280.1630640313.

The spelling of 21990375 in words is "twenty-one million, nine hundred ninety thousand, three hundred seventy-five".