155381 has 2 divisors, whose sum is σ = 155382. Its totient is φ = 155380.

The previous prime is 155377. The next prime is 155383. The reversal of 155381 is 183551.

155381 is nontrivially palindromic in base 13.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 152881 + 2500 = 391^2 + 50^2 .

It is a cyclic number.

It is not a de Polignac number, because 155381 - 2² = 155377 is a prime.

It is a super-2 number, since 2×155381² = 48286510322, which contains 22 as substring.

Together with 155383, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77690 + 77691.

It is an arithmetic number, because the mean of its divisors is an integer number (77691).

2¹⁵⁵³⁸¹ is an apocalyptic number.

It is an amenable number.

155381 is a deficient number, since it is larger than the sum of its proper divisors (1).

155381 is an equidigital number, since it uses as much as digits as its factorization.

155381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 600, while the sum is 23.

The square root of 155381 is about 394.1839672031. The cubic root of 155381 is about 53.7608307001.

The spelling of 155381 in words is "one hundred fifty-five thousand, three hundred eighty-one".