21628636 has 12 divisors (see below), whose sum is σ = 38101840. Its totient is φ = 10742400.

The previous prime is 21628627. The next prime is 21628643. The reversal of 21628636 is 63682612.

It is a happy number.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17301 + ... + 18508.

Almost surely, 2^21628636 is an apocalyptic number.

It is an amenable number.

21628636 is a deficient number, since it is larger than the sum of its proper divisors (16473204).

21628636 is a wasteful number, since it uses less digits than its factorization.

21628636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35964 (or 35962 counting only the distinct ones).

The product of its digits is 20736, while the sum is 34.

The square root of 21628636 is about 4650.6597381447. The cubic root of 21628636 is about 278.6183465385.

The spelling of 21628636 in words is "twenty-one million, six hundred twenty-eight thousand, six hundred thirty-six".