21660704 has 24 divisors (see below), whose sum is σ = 45925740. Its totient is φ = 9997056.

The previous prime is 21660701. The next prime is 21660713. The reversal of 21660704 is 40706612.

It can be written as a sum of positive squares in 2 ways, for example, as 21641104 + 19600 = 4652^2 + 140^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is not an unprimeable number, because it can be changed into a prime (21660701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25619 + ... + 26450.

Almost surely, 2^21660704 is an apocalyptic number.

It is an amenable number.

21660704 is an abundant number, since it is smaller than the sum of its proper divisors (24265036).

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

21660704 is a wasteful number, since it uses less digits than its factorization.

21660704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52092 (or 52084 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 21660704 is about 4654.1061440410. The cubic root of 21660704 is about 278.7559776715.

The spelling of 21660704 in words is "twenty-one million, six hundred sixty thousand, seven hundred four".