21231642 has 16 divisors (see below), whose sum is σ = 42536160. Its totient is φ = 7065072.

The previous prime is 21231631. The next prime is 21231677. The reversal of 21231642 is 24613212.

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, 1209 + ... + 6627.

It is an arithmetic number, because the mean of its divisors is an integer number (2658510).

Almost surely, 2^21231642 is an apocalyptic number.

21231642 is an abundant number, since it is smaller than the sum of its proper divisors (21304518).

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

21231642 is a wasteful number, since it uses less digits than its factorization.

21231642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6077.

The product of its digits is 576, while the sum is 21.

The square root of 21231642 is about 4607.7805937349. The cubic root of 21231642 is about 276.9031274684.

Adding to 21231642 its reverse (24613212), we get a palindrome (45844854).

The spelling of 21231642 in words is "twenty-one million, two hundred thirty-one thousand, six hundred forty-two".