21089982 has 32 divisors (see below), whose sum is σ = 44181504. Its totient is φ = 6703200.

The previous prime is 21089969. The next prime is 21089983. The reversal of 21089982 is 28998012.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 21089982.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21089983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12408 + ... + 14004.

It is an arithmetic number, because the mean of its divisors is an integer number (1380672).

Almost surely, 2^21089982 is an apocalyptic number.

21089982 is an abundant number, since it is smaller than the sum of its proper divisors (23091522).

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

21089982 is a wasteful number, since it uses less digits than its factorization.

21089982 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1704.

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 21089982 is about 4592.3830415156. The cubic root of 21089982 is about 276.2859093523.

It can be divided in two parts, 2108 and 9982, that added together give a triangular number (12090 = T₁₅₅).

The spelling of 21089982 in words is "twenty-one million, eighty-nine thousand, nine hundred eighty-two".