21533456 has 20 divisors (see below), whose sum is σ = 47681472. Its totient is φ = 9228576.

The previous prime is 21533443. The next prime is 21533459. The reversal of 21533456 is 65433512.

It is not an unprimeable number, because it can be changed into a prime (21533459) 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, 96020 + ... + 96243.

Almost surely, 2^21533456 is an apocalyptic number.

It is an amenable number.

21533456 is an abundant number, since it is smaller than the sum of its proper divisors (26148016).

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

21533456 is a wasteful number, since it uses less digits than its factorization.

21533456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192278 (or 192272 counting only the distinct ones).

The product of its digits is 10800, while the sum is 29.

The square root of 21533456 is about 4640.4154986380. The cubic root of 21533456 is about 278.2090451890.

Adding to 21533456 its reverse (65433512), we get a palindrome (86966968).

The spelling of 21533456 in words is "twenty-one million, five hundred thirty-three thousand, four hundred fifty-six".