399997187 has 2 divisors, whose sum is σ = 399997188. Its totient is φ = 399997186.

The previous prime is 399997153. The next prime is 399997193. The reversal of 399997187 is 781799993.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 399997187 - 2¹⁴ = 399980803 is a prime.

It is not a weakly prime, because it can be changed into another prime (399997127) 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, 199998593 + 199998594.

It is an arithmetic number, because the mean of its divisors is an integer number (199998594).

Almost surely, 2^399997187 is an apocalyptic number.

399997187 is a deficient number, since it is larger than the sum of its proper divisors (1).

399997187 is an equidigital number, since it uses as much as digits as its factorization.

399997187 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7715736, while the sum is 62.

The square root of 399997187 is about 19999.9296748764. The cubic root of 399997187 is about 736.8045725273.

The spelling of 399997187 in words is "three hundred ninety-nine million, nine hundred ninety-seven thousand, one hundred eighty-seven".