21431982 has 32 divisors (see below), whose sum is σ = 50359680. Its totient is φ = 5994720.

The previous prime is 21431959. The next prime is 21431983. The reversal of 21431982 is 28913412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21431983) 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, 11632 + ... + 13347.

It is an arithmetic number, because the mean of its divisors is an integer number (1573740).

Almost surely, 2^21431982 is an apocalyptic number.

21431982 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21431982 is an abundant number, since it is smaller than the sum of its proper divisors (28927698).

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

21431982 is a wasteful number, since it uses less digits than its factorization.

21431982 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25008.

The product of its digits is 3456, while the sum is 30.

The square root of 21431982 is about 4629.4688680236. The cubic root of 21431982 is about 277.7713472763.

The spelling of 21431982 in words is "twenty-one million, four hundred thirty-one thousand, nine hundred eighty-two".