198951691 has 2 divisors, whose sum is σ = 198951692. Its totient is φ = 198951690.

The previous prime is 198951671. The next prime is 198951737. The reversal of 198951691 is 196159891.

It is a weak prime.

It is an emirp because it is prime and its reverse (196159891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 198951691 - 2¹¹ = 198949643 is a prime.

It is not a weakly prime, because it can be changed into another prime (198951601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99475845 + 99475846.

It is an arithmetic number, because the mean of its divisors is an integer number (99475846).

Almost surely, 2^198951691 is an apocalyptic number.

198951691 is a deficient number, since it is larger than the sum of its proper divisors (1).

198951691 is an equidigital number, since it uses as much as digits as its factorization.

198951691 is an evil number, because the sum of its binary digits is even.

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

The square root of 198951691 is about 14105.0236086297. The cubic root of 198951691 is about 583.7799991919.

The spelling of 198951691 in words is "one hundred ninety-eight million, nine hundred fifty-one thousand, six hundred ninety-one".