199408071866 has 4 divisors (see below), whose sum is σ = 299112107802. Its totient is φ = 99704035932.

The previous prime is 199408071853. The next prime is 199408071899. The reversal of 199408071866 is 668170804991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 668170804991 = 52183 ⋅12804377.

It can be written as a sum of positive squares in only one way, i.e., 140909393641 + 58498678225 = 375379^2 + 241865^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49852017965 + ... + 49852017968.

Almost surely, 2^199408071866 is an apocalyptic number.

199408071866 is a deficient number, since it is larger than the sum of its proper divisors (99704035936).

199408071866 is an equidigital number, since it uses as much as digits as its factorization.

199408071866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99704035935.

The product of its (nonzero) digits is 5225472, while the sum is 59.

The spelling of 199408071866 in words is "one hundred ninety-nine billion, four hundred eight million, seventy-one thousand, eight hundred sixty-six".