199400891 has 4 divisors (see below), whose sum is σ = 199429800. Its totient is φ = 199371984.

The previous prime is 199400867. The next prime is 199400963. The reversal of 199400891 is 198004991.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 199400891 - 2⁶ = 199400827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (199400821) 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, 2600 + ... + 20138.

It is an arithmetic number, because the mean of its divisors is an integer number (49857450).

Almost surely, 2^199400891 is an apocalyptic number.

199400891 is a deficient number, since it is larger than the sum of its proper divisors (28909).

199400891 is a wasteful number, since it uses less digits than its factorization.

199400891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28908.

The product of its (nonzero) digits is 23328, while the sum is 41.

The square root of 199400891 is about 14120.9380354139. The cubic root of 199400891 is about 584.2190284879.

The spelling of 199400891 in words is "one hundred ninety-nine million, four hundred thousand, eight hundred ninety-one".