198731999 has 2 divisors, whose sum is σ = 198732000. Its totient is φ = 198731998.

The previous prime is 198731987. The next prime is 198732031. The reversal of 198731999 is 999137891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 198731999 - 2²⁴ = 181954783 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198731909) 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, 99365999 + 99366000.

It is an arithmetic number, because the mean of its divisors is an integer number (99366000).

Almost surely, 2^198731999 is an apocalyptic number.

198731999 is a deficient number, since it is larger than the sum of its proper divisors (1).

198731999 is an equidigital number, since it uses as much as digits as its factorization.

198731999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1102248, while the sum is 56.

The square root of 198731999 is about 14097.2337357370. The cubic root of 198731999 is about 583.5650407579.

The spelling of 198731999 in words is "one hundred ninety-eight million, seven hundred thirty-one thousand, nine hundred ninety-nine".