155949217 has 2 divisors, whose sum is σ = 155949218. Its totient is φ = 155949216.

The previous prime is 155949203. The next prime is 155949221. The reversal of 155949217 is 712949551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 117310561 + 38638656 = 10831^2 + 6216^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155949217 is a prime.

It is not a weakly prime, because it can be changed into another prime (155949817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77974608 + 77974609.

It is an arithmetic number, because the mean of its divisors is an integer number (77974609).

Almost surely, 2^155949217 is an apocalyptic number.

It is an amenable number.

155949217 is a deficient number, since it is larger than the sum of its proper divisors (1).

155949217 is an equidigital number, since it uses as much as digits as its factorization.

155949217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 113400, while the sum is 43.

The square root of 155949217 is about 12487.9628843138. The cubic root of 155949217 is about 538.2628412609.

The spelling of 155949217 in words is "one hundred fifty-five million, nine hundred forty-nine thousand, two hundred seventeen".