199438991 has 8 divisors (see below), whose sum is σ = 215610480. Its totient is φ = 183835008.

The previous prime is 199438963. The next prime is 199439041. The reversal of 199438991 is 199834991.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199438991 is a prime.

It is a super-2 number, since 2×199438991² = 79551822262196162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199438901) 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, 141146 + ... + 142551.

It is an arithmetic number, because the mean of its divisors is an integer number (26951310).

Almost surely, 2^199438991 is an apocalyptic number.

199438991 is a deficient number, since it is larger than the sum of its proper divisors (16171489).

199438991 is a wasteful number, since it uses less digits than its factorization.

199438991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283753.

The product of its digits is 629856, while the sum is 53.

The square root of 199438991 is about 14122.2870314974. The cubic root of 199438991 is about 584.2562354890.

The spelling of 199438991 in words is "one hundred ninety-nine million, four hundred thirty-eight thousand, nine hundred ninety-one".