21633426 has 16 divisors (see below), whose sum is σ = 48074400. Its totient is φ = 7211124.

The previous prime is 21633421. The next prime is 21633427. The reversal of 21633426 is 62433612.

21633426 is a `hidden beast` number, since 2 + 1 + 633 + 4 + 26 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21633426.

It is not an unprimeable number, because it can be changed into a prime (21633421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 200256 + ... + 200363.

It is an arithmetic number, because the mean of its divisors is an integer number (3004650).

Almost surely, 2^21633426 is an apocalyptic number.

21633426 is an abundant number, since it is smaller than the sum of its proper divisors (26440974).

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

21633426 is a wasteful number, since it uses less digits than its factorization.

21633426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400630 (or 400624 counting only the distinct ones).

The product of its digits is 5184, while the sum is 27.

The square root of 21633426 is about 4651.1746903336. The cubic root of 21633426 is about 278.6389131517.

The spelling of 21633426 in words is "twenty-one million, six hundred thirty-three thousand, four hundred twenty-six".