21650660 has 12 divisors (see below), whose sum is σ = 45466428. Its totient is φ = 8660256.

The previous prime is 21650653. The next prime is 21650683. The reversal of 21650660 is 6605612.

It can be written as a sum of positive squares in 2 ways, for example, as 2483776 + 19166884 = 1576^2 + 4378^2 .

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, 541247 + ... + 541286.

It is an arithmetic number, because the mean of its divisors is an integer number (3788869).

Almost surely, 2^21650660 is an apocalyptic number.

21650660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21650660 is an abundant number, since it is smaller than the sum of its proper divisors (23815768).

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

21650660 is a wasteful number, since it uses less digits than its factorization.

21650660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1082542 (or 1082540 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 21650660 is about 4653.0269717679. The cubic root of 21650660 is about 278.7128849215.

The spelling of 21650660 in words is "twenty-one million, six hundred fifty thousand, six hundred sixty".