155361989 has 2 divisors, whose sum is σ = 155361990. Its totient is φ = 155361988.

The previous prime is 155361959. The next prime is 155362057. The reversal of 155361989 is 989163551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 111471364 + 43890625 = 10558^2 + 6625^2 .

It is a cyclic number.

It is not a de Polignac number, because 155361989 - 2²⁰ = 154313413 is a prime.

It is a super-2 number, since 2×155361989² = 48274695252072242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155361959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77680994 + 77680995.

It is an arithmetic number, because the mean of its divisors is an integer number (77680995).

Almost surely, 2^155361989 is an apocalyptic number.

It is an amenable number.

155361989 is a deficient number, since it is larger than the sum of its proper divisors (1).

155361989 is an equidigital number, since it uses as much as digits as its factorization.

155361989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 291600, while the sum is 47.

The square root of 155361989 is about 12464.4289480104. The cubic root of 155361989 is about 537.5863804926.

The spelling of 155361989 in words is "one hundred fifty-five million, three hundred sixty-one thousand, nine hundred eighty-nine".