199161991 has 8 divisors (see below), whose sum is σ = 237510144. Its totient is φ = 163287960.

The previous prime is 199161961. The next prime is 199161997.

199161991 is nontrivially palindromic in base 10.

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

It is a cyclic number.

It is not a de Polignac number, because 199161991 - 2⁵ = 199161959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199161997) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 618355 + ... + 618676.

It is an arithmetic number, because the mean of its divisors is an integer number (29688768).

Almost surely, 2^199161991 is an apocalyptic number.

199161991 is a deficient number, since it is larger than the sum of its proper divisors (38348153).

199161991 is a wasteful number, since it uses less digits than its factorization.

199161991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1237061.

The product of its digits is 39366, while the sum is 46.

The square root of 199161991 is about 14112.4764304498. The cubic root of 199161991 is about 583.9856197982.

The spelling of 199161991 in words is "one hundred ninety-nine million, one hundred sixty-one thousand, nine hundred ninety-one".