21432436 has 6 divisors (see below), whose sum is σ = 37506770. Its totient is φ = 10716216.

The previous prime is 21432413. The next prime is 21432443. The reversal of 21432436 is 63423412.

It can be written as a sum of positive squares in only one way, i.e., 20611600 + 820836 = 4540^2 + 906^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21432436.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2679051 + ... + 2679058.

Almost surely, 2^21432436 is an apocalyptic number.

It is an amenable number.

21432436 is a deficient number, since it is larger than the sum of its proper divisors (16074334).

21432436 is a wasteful number, since it uses less digits than its factorization.

21432436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5358113 (or 5358111 counting only the distinct ones).

The product of its digits is 3456, while the sum is 25.

The square root of 21432436 is about 4629.5179014666. The cubic root of 21432436 is about 277.7733086333.

Adding to 21432436 its reverse (63423412), we get a palindrome (84855848).

The spelling of 21432436 in words is "twenty-one million, four hundred thirty-two thousand, four hundred thirty-six".