199615891 has 2 divisors, whose sum is σ = 199615892. Its totient is φ = 199615890.

The previous prime is 199615849. The next prime is 199615931. The reversal of 199615891 is 198516991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 199615891 - 2¹⁹ = 199091603 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (199616891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99807945 + 99807946.

It is an arithmetic number, because the mean of its divisors is an integer number (99807946).

Almost surely, 2^199615891 is an apocalyptic number.

199615891 is a deficient number, since it is larger than the sum of its proper divisors (1).

199615891 is an equidigital number, since it uses as much as digits as its factorization.

199615891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 174960, while the sum is 49.

The square root of 199615891 is about 14128.5487931351. The cubic root of 199615891 is about 584.4289272052.

It can be divided in two parts, 19961 and 5891, that added together give a palindrome (25852).

The spelling of 199615891 in words is "one hundred ninety-nine million, six hundred fifteen thousand, eight hundred ninety-one".