21440432 has 20 divisors (see below), whose sum is σ = 44736720. Its totient is φ = 9895488.

The previous prime is 21440431. The next prime is 21440449. The reversal of 21440432 is 23404412.

It is not an unprimeable number, because it can be changed into a prime (21440431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51332 + ... + 51747.

It is an arithmetic number, because the mean of its divisors is an integer number (2236836).

Almost surely, 2^21440432 is an apocalyptic number.

It is an amenable number.

21440432 is an abundant number, since it is smaller than the sum of its proper divisors (23296288).

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

21440432 is a wasteful number, since it uses less digits than its factorization.

21440432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 103100 (or 103094 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 21440432 is about 4630.3814097761. The cubic root of 21440432 is about 277.8078481698.

Adding to 21440432 its reverse (23404412), we get a palindrome (44844844).

The spelling of 21440432 in words is "twenty-one million, four hundred forty thousand, four hundred thirty-two".