155391 has 4 divisors (see below), whose sum is σ = 207192. Its totient is φ = 103592.

The previous prime is 155387. The next prime is 155399. The reversal of 155391 is 193551.

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 155391 - 2² = 155387 is a prime.

It is a D-number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155399) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25896 + ... + 25901.

It is an arithmetic number, because the mean of its divisors is an integer number (51798).

2¹⁵⁵³⁹¹ is an apocalyptic number.

155391 is a deficient number, since it is larger than the sum of its proper divisors (51801).

155391 is an equidigital number, since it uses as much as digits as its factorization.

155391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51800.

The product of its digits is 675, while the sum is 24.

The square root of 155391 is about 394.1966514317. The cubic root of 155391 is about 53.7619839873.

The spelling of 155391 in words is "one hundred fifty-five thousand, three hundred ninety-one".