155645989 has 2 divisors, whose sum is σ = 155645990. Its totient is φ = 155645988.

The previous prime is 155645981. The next prime is 155646011. The reversal of 155645989 is 989546551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 154181889 + 1464100 = 12417^2 + 1210^2 .

It is a cyclic number.

It is not a de Polignac number, because 155645989 - 2³ = 155645981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155645981) 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, 77822994 + 77822995.

It is an arithmetic number, because the mean of its divisors is an integer number (77822995).

Almost surely, 2^155645989 is an apocalyptic number.

It is an amenable number.

155645989 is a deficient number, since it is larger than the sum of its proper divisors (1).

155645989 is an equidigital number, since it uses as much as digits as its factorization.

155645989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944000, while the sum is 52.

The square root of 155645989 is about 12475.8161656863. The cubic root of 155645989 is about 537.9137484206.

The spelling of 155645989 in words is "one hundred fifty-five million, six hundred forty-five thousand, nine hundred eighty-nine".