155813231 has 4 divisors (see below), whose sum is σ = 178072272. Its totient is φ = 133554192.

The previous prime is 155813227. The next prime is 155813239. The reversal of 155813231 is 132318551.

It is a happy number.

155813231 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 132318551 = 439 ⋅301409.

It is a cyclic number.

It is not a de Polignac number, because 155813231 - 2² = 155813227 is a prime.

It is a super-2 number, since 2×155813231² = 48555525909318722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 155813194 and 155813203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155813239) 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, 11129510 + ... + 11129523.

It is an arithmetic number, because the mean of its divisors is an integer number (44518068).

Almost surely, 2^155813231 is an apocalyptic number.

155813231 is a deficient number, since it is larger than the sum of its proper divisors (22259041).

155813231 is an equidigital number, since it uses as much as digits as its factorization.

155813231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22259040.

The product of its digits is 3600, while the sum is 29.

The square root of 155813231 is about 12482.5170138078. The cubic root of 155813231 is about 538.1063426736.

The spelling of 155813231 in words is "one hundred fifty-five million, eight hundred thirteen thousand, two hundred thirty-one".