155401331 has 2 divisors, whose sum is σ = 155401332. Its totient is φ = 155401330.

The previous prime is 155401313. The next prime is 155401333. The reversal of 155401331 is 133104551.

155401331 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

Together with previous prime (155401313) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 155401331 - 2¹⁰ = 155400307 is a prime.

It is a super-2 number, since 2×155401331² = 48299147353143122, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 155401333, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 155401297 and 155401306.

It is not a weakly prime, because it can be changed into another prime (155401333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77700665 + 77700666.

It is an arithmetic number, because the mean of its divisors is an integer number (77700666).

Almost surely, 2^155401331 is an apocalyptic number.

155401331 is a deficient number, since it is larger than the sum of its proper divisors (1).

155401331 is an equidigital number, since it uses as much as digits as its factorization.

155401331 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 155401331 is about 12466.0070190900. The cubic root of 155401331 is about 537.6317539642.

Adding to 155401331 its reverse (133104551), we get a palindrome (288505882).

The spelling of 155401331 in words is "one hundred fifty-five million, four hundred one thousand, three hundred thirty-one".