20664959 has 8 divisors (see below), whose sum is σ = 23776800. Its totient is φ = 17593056.

The previous prime is 20664953. The next prime is 20664961. The reversal of 20664959 is 95946602.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20664959 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20664953) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8864 + ... + 10949.

It is an arithmetic number, because the mean of its divisors is an integer number (2972100).

Almost surely, 2^20664959 is an apocalyptic number.

20664959 is a deficient number, since it is larger than the sum of its proper divisors (3111841).

20664959 is a wasteful number, since it uses less digits than its factorization.

20664959 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19969.

The product of its (nonzero) digits is 116640, while the sum is 41.

The square root of 20664959 is about 4545.8727434894. The cubic root of 20664959 is about 274.4173183274.

The spelling of 20664959 in words is "twenty million, six hundred sixty-four thousand, nine hundred fifty-nine".