199928391 has 8 divisors (see below), whose sum is σ = 287076720. Its totient is φ = 123032832.

The previous prime is 199928387. The next prime is 199928419. The reversal of 199928391 is 193829991.

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

It is not a de Polignac number, because 199928391 - 2² = 199928387 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199928191) 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, 2563146 + ... + 2563223.

It is an arithmetic number, because the mean of its divisors is an integer number (35884590).

Almost surely, 2^199928391 is an apocalyptic number.

199928391 is a deficient number, since it is larger than the sum of its proper divisors (87148329).

199928391 is a wasteful number, since it uses less digits than its factorization.

199928391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5126385.

The product of its digits is 314928, while the sum is 51.

The square root of 199928391 is about 14139.6036365946. The cubic root of 199928391 is about 584.7337439822.

The spelling of 199928391 in words is "one hundred ninety-nine million, nine hundred twenty-eight thousand, three hundred ninety-one".