20715666 has 16 divisors (see below), whose sum is σ = 41484864. Its totient is φ = 6896304.

The previous prime is 20715659. The next prime is 20715683. The reversal of 20715666 is 66651702.

It is a Curzon number.

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, 4251 + ... + 7713.

It is an arithmetic number, because the mean of its divisors is an integer number (2592804).

Almost surely, 2^20715666 is an apocalyptic number.

20715666 is an abundant number, since it is smaller than the sum of its proper divisors (20769198).

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

20715666 is a wasteful number, since it uses less digits than its factorization.

20715666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4465.

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 20715666 is about 4551.4465832304. The cubic root of 20715666 is about 274.6415870708.

The spelling of 20715666 in words is "twenty million, seven hundred fifteen thousand, six hundred sixty-six".