21783690 has 48 divisors (see below), whose sum is σ = 59623200. Its totient is φ = 5502816.

The previous prime is 21783683. The next prime is 21783703. The reversal of 21783690 is 9638712.

It is a super-2 number, since 2×21783690² = 949058300032200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4660 + ... + 8079.

It is an arithmetic number, because the mean of its divisors is an integer number (1242150).

Almost surely, 2^21783690 is an apocalyptic number.

21783690 is an abundant number, since it is smaller than the sum of its proper divisors (37839510).

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

21783690 is a wasteful number, since it uses less digits than its factorization.

21783690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12771 (or 12768 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 21783690 is about 4667.3000760611. The cubic root of 21783690 is about 279.2825595400.

The spelling of 21783690 in words is "twenty-one million, seven hundred eighty-three thousand, six hundred ninety".