156199909 has 2 divisors, whose sum is σ = 156199910. Its totient is φ = 156199908.

The previous prime is 156199907. The next prime is 156199933. The reversal of 156199909 is 909991651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 156000100 + 199809 = 12490^2 + 447^2 .

It is an emirp because it is prime and its reverse (909991651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 156199909 - 2¹ = 156199907 is a prime.

Together with 156199907, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (156199907) 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, 78099954 + 78099955.

It is an arithmetic number, because the mean of its divisors is an integer number (78099955).

Almost surely, 2^156199909 is an apocalyptic number.

It is an amenable number.

156199909 is a deficient number, since it is larger than the sum of its proper divisors (1).

156199909 is an equidigital number, since it uses as much as digits as its factorization.

156199909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 196830, while the sum is 49.

The square root of 156199909 is about 12497.9961993913. The cubic root of 156199909 is about 538.5511102027.

The spelling of 156199909 in words is "one hundred fifty-six million, one hundred ninety-nine thousand, nine hundred nine".