155840609 has 2 divisors, whose sum is σ = 155840610. Its totient is φ = 155840608.

The previous prime is 155840563. The next prime is 155840623. The reversal of 155840609 is 906048551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83539600 + 72301009 = 9140^2 + 8503^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155840609 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is equal to p_8754167 and since 155840609 and 8754167 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (155843609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77920304 + 77920305.

It is an arithmetic number, because the mean of its divisors is an integer number (77920305).

Almost surely, 2^155840609 is an apocalyptic number.

It is an amenable number.

155840609 is a deficient number, since it is larger than the sum of its proper divisors (1).

155840609 is an equidigital number, since it uses as much as digits as its factorization.

155840609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43200, while the sum is 38.

The square root of 155840609 is about 12483.6136194613. The cubic root of 155840609 is about 538.1378577821.

The spelling of 155840609 in words is "one hundred fifty-five million, eight hundred forty thousand, six hundred nine".