199609866 has 16 divisors (see below), whose sum is σ = 443577600. Its totient is φ = 66536604.

The previous prime is 199609859. The next prime is 199609901. The reversal of 199609866 is 668906991.

It is a Harshad number since it is a multiple of its sum of digits (54), and also a Moran number because the ratio is a prime number: 3696479 = 199609866 / (1 + 9 + 9 + 6 + 0 + 9 + 8 + 6 + 6).

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, 1848186 + ... + 1848293.

It is an arithmetic number, because the mean of its divisors is an integer number (27723600).

Almost surely, 2^199609866 is an apocalyptic number.

199609866 is an abundant number, since it is smaller than the sum of its proper divisors (243967734).

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

199609866 is a wasteful number, since it uses less digits than its factorization.

199609866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3696490 (or 3696484 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 54.

The square root of 199609866 is about 14128.3355707599. The cubic root of 199609866 is about 584.4230472129.

The spelling of 199609866 in words is "one hundred ninety-nine million, six hundred nine thousand, eight hundred sixty-six".