21432455 has 16 divisors (see below), whose sum is σ = 28162944. Its totient is φ = 15528480.

The previous prime is 21432443. The next prime is 21432473. The reversal of 21432455 is 55423412.

It is a happy number.

It is not a de Polignac number, because 21432455 - 2⁸ = 21432199 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18524 + ... + 19646.

It is an arithmetic number, because the mean of its divisors is an integer number (1760184).

Almost surely, 2^21432455 is an apocalyptic number.

21432455 is a deficient number, since it is larger than the sum of its proper divisors (6730489).

21432455 is a wasteful number, since it uses less digits than its factorization.

21432455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1486.

The product of its digits is 4800, while the sum is 26.

The square root of 21432455 is about 4629.5199535157. The cubic root of 21432455 is about 277.7733907159.

Adding to 21432455 its reverse (55423412), we get a palindrome (76855867).

The spelling of 21432455 in words is "twenty-one million, four hundred thirty-two thousand, four hundred fifty-five".