21432812 has 24 divisors (see below), whose sum is σ = 38419920. Its totient is φ = 10458560.

The previous prime is 21432809. The next prime is 21432821. The reversal of 21432812 is 21823412.

It is a happy number.

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, 46262 + ... + 46722.

It is an arithmetic number, because the mean of its divisors is an integer number (1600830).

Almost surely, 2^21432812 is an apocalyptic number.

It is an amenable number.

21432812 is a deficient number, since it is larger than the sum of its proper divisors (16987108).

21432812 is a wasteful number, since it uses less digits than its factorization.

21432812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 721 (or 719 counting only the distinct ones).

The product of its digits is 768, while the sum is 23.

The square root of 21432812 is about 4629.5585102686. The cubic root of 21432812 is about 277.7749329961.

The spelling of 21432812 in words is "twenty-one million, four hundred thirty-two thousand, eight hundred twelve".