198465991 has 2 divisors, whose sum is σ = 198465992. Its totient is φ = 198465990.

The previous prime is 198465959. The next prime is 198465997. The reversal of 198465991 is 199564891.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (199564891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 198465991 - 2⁵ = 198465959 is a prime.

It is a super-2 number, since 2×198465991² = 78777499167224162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198465997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99232995 + 99232996.

It is an arithmetic number, because the mean of its divisors is an integer number (99232996).

Almost surely, 2^198465991 is an apocalyptic number.

198465991 is a deficient number, since it is larger than the sum of its proper divisors (1).

198465991 is an equidigital number, since it uses as much as digits as its factorization.

198465991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 699840, while the sum is 52.

The square root of 198465991 is about 14087.7958176572. The cubic root of 198465991 is about 583.3045521219.

The spelling of 198465991 in words is "one hundred ninety-eight million, four hundred sixty-five thousand, nine hundred ninety-one".