19920565666 has 8 divisors (see below), whose sum is σ = 29927321424. Its totient is φ = 9944791860.

The previous prime is 19920565663. The next prime is 19920565699. The reversal of 19920565666 is 66656502991.

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

It is not an unprimeable number, because it can be changed into a prime (19920565663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7743880 + ... + 7746451.

It is an arithmetic number, because the mean of its divisors is an integer number (3740915178).

Almost surely, 2^19920565666 is an apocalyptic number.

19920565666 is a deficient number, since it is larger than the sum of its proper divisors (10006755758).

19920565666 is a wasteful number, since it uses less digits than its factorization.

19920565666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15490976.

The product of its (nonzero) digits is 5248800, while the sum is 55.

The spelling of 19920565666 in words is "nineteen billion, nine hundred twenty million, five hundred sixty-five thousand, six hundred sixty-six".