21497982 has 32 divisors (see below), whose sum is σ = 47101824. Its totient is φ = 6487200.

The previous prime is 21497977. The next prime is 21498041. The reversal of 21497982 is 28979412.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19732 + ... + 20792.

It is an arithmetic number, because the mean of its divisors is an integer number (1471932).

Almost surely, 2^21497982 is an apocalyptic number.

21497982 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21497982 is an abundant number, since it is smaller than the sum of its proper divisors (25603842).

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

21497982 is a wasteful number, since it uses less digits than its factorization.

21497982 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1384.

The product of its digits is 72576, while the sum is 42.

The square root of 21497982 is about 4636.5916361051. The cubic root of 21497982 is about 278.0561882873.

The spelling of 21497982 in words is "twenty-one million, four hundred ninety-seven thousand, nine hundred eighty-two".