199742891 has 2 divisors, whose sum is σ = 199742892. Its totient is φ = 199742890.

The previous prime is 199742887. The next prime is 199742899. The reversal of 199742891 is 198247991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 199742891 - 2² = 199742887 is a prime.

It is not a weakly prime, because it can be changed into another prime (199742899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99871445 + 99871446.

It is an arithmetic number, because the mean of its divisors is an integer number (99871446).

Almost surely, 2^199742891 is an apocalyptic number.

199742891 is a deficient number, since it is larger than the sum of its proper divisors (1).

199742891 is an equidigital number, since it uses as much as digits as its factorization.

199742891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 326592, while the sum is 50.

The square root of 199742891 is about 14133.0425245239. The cubic root of 199742891 is about 584.5528430890.

The spelling of 199742891 in words is "one hundred ninety-nine million, seven hundred forty-two thousand, eight hundred ninety-one".