21431432 has 16 divisors (see below), whose sum is σ = 43837200. Its totient is φ = 9741520.

The previous prime is 21431401. The next prime is 21431489. The reversal of 21431432 is 23413412.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121682 + ... + 121857.

It is an arithmetic number, because the mean of its divisors is an integer number (2739825).

Almost surely, 2^21431432 is an apocalyptic number.

21431432 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21431432 is an abundant number, since it is smaller than the sum of its proper divisors (22405768).

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

21431432 is a wasteful number, since it uses less digits than its factorization.

21431432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243556 (or 243552 counting only the distinct ones).

The product of its digits is 576, while the sum is 20.

The square root of 21431432 is about 4629.4094655798. The cubic root of 21431432 is about 277.7689711460.

Adding to 21431432 its reverse (23413412), we get a palindrome (44844844).

It can be divided in two parts, 2 and 1431432, that multiplied together give a square (2862864 = 1692²).

The spelling of 21431432 in words is "twenty-one million, four hundred thirty-one thousand, four hundred thirty-two".