21431032 has 48 divisors (see below), whose sum is σ = 48796560. Its totient is φ = 8781696.

The previous prime is 21431023. The next prime is 21431057. The reversal of 21431032 is 23013412.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21430997 and 21431015.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7828 + ... + 10204.

It is an arithmetic number, because the mean of its divisors is an integer number (1016595).

Almost surely, 2^21431032 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21431032, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24398280).

21431032 is an abundant number, since it is smaller than the sum of its proper divisors (27365528).

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

21431032 is a wasteful number, since it uses less digits than its factorization.

21431032 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2420 (or 2409 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21431032 is about 4629.3662633237. The cubic root of 21431032 is about 277.7672430257.

Adding to 21431032 its reverse (23013412), we get a palindrome (44444444).

The spelling of 21431032 in words is "twenty-one million, four hundred thirty-one thousand, thirty-two".