21991182 has 16 divisors (see below), whose sum is σ = 44513280. Its totient is φ = 7241912.

The previous prime is 21991163. The next prime is 21991199. The reversal of 21991182 is 28119912.

It is a super-2 number, since 2×21991182² = 967224171514248, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21582 + ... + 22577.

It is an arithmetic number, because the mean of its divisors is an integer number (2782080).

Almost surely, 2^21991182 is an apocalyptic number.

21991182 is an abundant number, since it is smaller than the sum of its proper divisors (22522098).

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

21991182 is a wasteful number, since it uses less digits than its factorization.

21991182 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44247.

The product of its digits is 2592, while the sum is 33.

The square root of 21991182 is about 4689.4756636537. The cubic root of 21991182 is about 280.1664911190.

The spelling of 21991182 in words is "twenty-one million, nine hundred ninety-one thousand, one hundred eighty-two".