155911 has 4 divisors (see below), whose sum is σ = 178192. Its totient is φ = 133632.

The previous prime is 155893. The next prime is 155921. The reversal of 155911 is 119551.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 155911 - 2⁷ = 155783 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11130 + ... + 11143.

It is an arithmetic number, because the mean of its divisors is an integer number (44548).

2¹⁵⁵⁹¹¹ is an apocalyptic number.

155911 is a deficient number, since it is larger than the sum of its proper divisors (22281).

155911 is an equidigital number, since it uses as much as digits as its factorization.

155911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22280.

The product of its digits is 225, while the sum is 22.

The square root of 155911 is about 394.8556698339. The cubic root of 155911 is about 53.8218868674.

The spelling of 155911 in words is "one hundred fifty-five thousand, nine hundred eleven".