21779136 has 42 divisors (see below), whose sum is σ = 62427612. Its totient is φ = 7259520.

The previous prime is 21779129. The next prime is 21779141. The reversal of 21779136 is 63197712.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21779136.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18330 + ... + 19481.

Almost surely, 2^21779136 is an apocalyptic number.

It is an amenable number.

21779136 is an abundant number, since it is smaller than the sum of its proper divisors (40648476).

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

21779136 is a wasteful number, since it uses less digits than its factorization.

21779136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37829 (or 37816 counting only the distinct ones).

The product of its digits is 15876, while the sum is 36.

The square root of 21779136 is about 4666.8121882073. The cubic root of 21779136 is about 279.2630963328.

The spelling of 21779136 in words is "twenty-one million, seven hundred seventy-nine thousand, one hundred thirty-six".