155872109 has 2 divisors, whose sum is σ = 155872110. Its totient is φ = 155872108.

The previous prime is 155872049. The next prime is 155872111. The reversal of 155872109 is 901278551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 131171209 + 24700900 = 11453^2 + 4970^2 .

It is an emirp because it is prime and its reverse (901278551) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155872109 is a prime.

It is a super-2 number, since 2×155872109² = 48592228728215762, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 155872111, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is equal to p_8755832 and since 155872109 and 8755832 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155872139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77936054 + 77936055.

It is an arithmetic number, because the mean of its divisors is an integer number (77936055).

Almost surely, 2^155872109 is an apocalyptic number.

It is an amenable number.

155872109 is a deficient number, since it is larger than the sum of its proper divisors (1).

155872109 is an equidigital number, since it uses as much as digits as its factorization.

155872109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25200, while the sum is 38.

The square root of 155872109 is about 12484.8752096286. The cubic root of 155872109 is about 538.1741132028.

The spelling of 155872109 in words is "one hundred fifty-five million, eight hundred seventy-two thousand, one hundred nine".