194399987 has 2 divisors, whose sum is σ = 194399988. Its totient is φ = 194399986.

The previous prime is 194399969. The next prime is 194400023. The reversal of 194399987 is 789993491.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 194399987 - 2⁶ = 194399923 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (194399957) 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, 97199993 + 97199994.

It is an arithmetic number, because the mean of its divisors is an integer number (97199994).

Almost surely, 2^194399987 is an apocalyptic number.

194399987 is a deficient number, since it is larger than the sum of its proper divisors (1).

194399987 is an equidigital number, since it uses as much as digits as its factorization.

194399987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4408992, while the sum is 59.

The square root of 194399987 is about 13942.7395801543. The cubic root of 194399987 is about 579.2936178505.

The spelling of 194399987 in words is "one hundred ninety-four million, three hundred ninety-nine thousand, nine hundred eighty-seven".