21776636 has 12 divisors (see below), whose sum is σ = 43553328. Its totient is φ = 9332832.

The previous prime is 21776611. The next prime is 21776647. The reversal of 21776636 is 63667712.

21776636 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 21776636.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 388841 + ... + 388896.

It is an arithmetic number, because the mean of its divisors is an integer number (3629444).

Almost surely, 2^21776636 is an apocalyptic number.

It is an amenable number.

21776636 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21776636 is a wasteful number, since it uses less digits than its factorization.

21776636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 777748 (or 777746 counting only the distinct ones).

The product of its digits is 63504, while the sum is 38.

The square root of 21776636 is about 4666.5443317299. The cubic root of 21776636 is about 279.2524105024.

The spelling of 21776636 in words is "twenty-one million, seven hundred seventy-six thousand, six hundred thirty-six".