155987609 has 2 divisors, whose sum is σ = 155987610. Its totient is φ = 155987608.

The previous prime is 155987551. The next prime is 155987647. The reversal of 155987609 is 906789551.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 152646025 + 3341584 = 12355^2 + 1828^2 .

It is an emirp because it is prime and its reverse (906789551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 155987609 - 2²⁰ = 154939033 is a prime.

It is not a weakly prime, because it can be changed into another prime (155987669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77993804 + 77993805.

It is an arithmetic number, because the mean of its divisors is an integer number (77993805).

Almost surely, 2^155987609 is an apocalyptic number.

It is an amenable number.

155987609 is a deficient number, since it is larger than the sum of its proper divisors (1).

155987609 is an equidigital number, since it uses as much as digits as its factorization.

155987609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 680400, while the sum is 50.

The square root of 155987609 is about 12489.4999499580. The cubic root of 155987609 is about 538.3070079708.

The spelling of 155987609 in words is "one hundred fifty-five million, nine hundred eighty-seven thousand, six hundred nine".