21990250 has 16 divisors (see below), whose sum is σ = 41166216. Its totient is φ = 8796000.

The previous prime is 21990193. The next prime is 21990257. The reversal of 21990250 is 5209912.

It can be written as a sum of positive squares in 4 ways, for example, as 1096209 + 20894041 = 1047^2 + 4571^2 .

It is not an unprimeable number, because it can be changed into a prime (21990257) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43731 + ... + 44230.

Almost surely, 2^21990250 is an apocalyptic number.

21990250 is a deficient number, since it is larger than the sum of its proper divisors (19175966).

21990250 is an equidigital number, since it uses as much as digits as its factorization.

21990250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87978 (or 87968 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 21990250 is about 4689.3762911500. The cubic root of 21990250 is about 280.1625331862.

The spelling of 21990250 in words is "twenty-one million, nine hundred ninety thousand, two hundred fifty".