19909666 has 8 divisors (see below), whose sum is σ = 34130880. Its totient is φ = 8532708.

The previous prime is 19909661. The next prime is 19909679. The reversal of 19909666 is 66690991.

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 (19909661) 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, 711046 + ... + 711073.

It is an arithmetic number, because the mean of its divisors is an integer number (4266360).

Almost surely, 2^19909666 is an apocalyptic number.

19909666 is a deficient number, since it is larger than the sum of its proper divisors (14221214).

19909666 is a wasteful number, since it uses less digits than its factorization.

19909666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1422128.

The product of its (nonzero) digits is 157464, while the sum is 46.

The square root of 19909666 is about 4462.0248766675. The cubic root of 19909666 is about 271.0324711572.

The spelling of 19909666 in words is "nineteen million, nine hundred nine thousand, six hundred sixty-six".