156555989 has 2 divisors, whose sum is σ = 156555990. Its totient is φ = 156555988.

The previous prime is 156555977. The next prime is 156556021. The reversal of 156555989 is 989555651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 97911025 + 58644964 = 9895^2 + 7658^2 .

It is a cyclic number.

It is not a de Polignac number, because 156555989 - 2²⁰ = 155507413 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 156555989.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (156555929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78277994 + 78277995.

It is an arithmetic number, because the mean of its divisors is an integer number (78277995).

Almost surely, 2^156555989 is an apocalyptic number.

It is an amenable number.

156555989 is a deficient number, since it is larger than the sum of its proper divisors (1).

156555989 is an equidigital number, since it uses as much as digits as its factorization.

156555989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2430000, while the sum is 53.

The square root of 156555989 is about 12512.2335735871. The cubic root of 156555989 is about 538.9600343490.

The spelling of 156555989 in words is "one hundred fifty-six million, five hundred fifty-five thousand, nine hundred eighty-nine".