210981990 has 32 divisors (see below), whose sum is σ = 528374016. Its totient is φ = 53815520.

The previous prime is 210981973. The next prime is 210982021. The reversal of 210981990 is 99189012.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 152196 + ... + 153575.

It is an arithmetic number, because the mean of its divisors is an integer number (16511688).

Almost surely, 2^210981990 is an apocalyptic number.

210981990 is an abundant number, since it is smaller than the sum of its proper divisors (317392026).

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

210981990 is a wasteful number, since it uses less digits than its factorization.

210981990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305804.

The product of its (nonzero) digits is 11664, while the sum is 39.

The square root of 210981990 is about 14525.2191033389. The cubic root of 210981990 is about 595.3172424929.

The spelling of 210981990 in words is "two hundred ten million, nine hundred eighty-one thousand, nine hundred ninety".