21940665 has 8 divisors (see below), whose sum is σ = 35105088. Its totient is φ = 11701680.

The previous prime is 21940657. The next prime is 21940679. The reversal of 21940665 is 56604912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21940665 - 2³ = 21940657 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 731341 + ... + 731370.

It is an arithmetic number, because the mean of its divisors is an integer number (4388136).

Almost surely, 2^21940665 is an apocalyptic number.

It is an amenable number.

21940665 is a deficient number, since it is larger than the sum of its proper divisors (13164423).

21940665 is a wasteful number, since it uses less digits than its factorization.

21940665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1462719.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 21940665 is about 4684.0863570178. The cubic root of 21940665 is about 279.9517986755.

The spelling of 21940665 in words is "twenty-one million, nine hundred forty thousand, six hundred sixty-five".