21866736 has 20 divisors (see below), whose sum is σ = 56489192. Its totient is φ = 7288896.

The previous prime is 21866729. The next prime is 21866737. The reversal of 21866736 is 63766812.

It is a junction number, because it is equal to n+sod(n) for n = 21866694 and 21866703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21866737) 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, 227731 + ... + 227826.

Almost surely, 2^21866736 is an apocalyptic number.

It is an amenable number.

21866736 is an abundant number, since it is smaller than the sum of its proper divisors (34622456).

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

21866736 is a wasteful number, since it uses less digits than its factorization.

21866736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455568 (or 455562 counting only the distinct ones).

The product of its digits is 72576, while the sum is 39.

The square root of 21866736 is about 4676.1881912515. The cubic root of 21866736 is about 279.6370126257.

The spelling of 21866736 in words is "twenty-one million, eight hundred sixty-six thousand, seven hundred thirty-six".