199785679 has 2 divisors, whose sum is σ = 199785680. Its totient is φ = 199785678.

The previous prime is 199785671. The next prime is 199785689. The reversal of 199785679 is 976587991.

It is a weak prime.

It is an emirp because it is prime and its reverse (976587991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199785679 - 2³ = 199785671 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199785671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99892839 + 99892840.

It is an arithmetic number, because the mean of its divisors is an integer number (99892840).

Almost surely, 2^199785679 is an apocalyptic number.

199785679 is a deficient number, since it is larger than the sum of its proper divisors (1).

199785679 is an equidigital number, since it uses as much as digits as its factorization.

199785679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8573040, while the sum is 61.

The square root of 199785679 is about 14134.5562010273. The cubic root of 199785679 is about 584.5945801794.

The spelling of 199785679 in words is "one hundred ninety-nine million, seven hundred eighty-five thousand, six hundred seventy-nine".