199428091 has 4 divisors (see below), whose sum is σ = 199631952. Its totient is φ = 199224232.

The previous prime is 199428079. The next prime is 199428107. The reversal of 199428091 is 190824991.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 199428091 - 2¹¹ = 199426043 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (199428011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 100456 + ... + 102421.

It is an arithmetic number, because the mean of its divisors is an integer number (49907988).

Almost surely, 2^199428091 is an apocalyptic number.

199428091 is a deficient number, since it is larger than the sum of its proper divisors (203861).

199428091 is an equidigital number, since it uses as much as digits as its factorization.

199428091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203860.

The product of its (nonzero) digits is 46656, while the sum is 43.

The square root of 199428091 is about 14121.9011113943. The cubic root of 199428091 is about 584.2455914503.

The spelling of 199428091 in words is "one hundred ninety-nine million, four hundred twenty-eight thousand, ninety-one".