155530231 has 2 divisors, whose sum is σ = 155530232. Its totient is φ = 155530230.

The previous prime is 155530213. The next prime is 155530253. The reversal of 155530231 is 132035551.

Together with previous prime (155530213) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is an emirp because it is prime and its reverse (132035551) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155530231 is a prime.

It is a super-2 number, since 2×155530231² = 48379305509826722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 155530196 and 155530205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155530201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77765115 + 77765116.

It is an arithmetic number, because the mean of its divisors is an integer number (77765116).

Almost surely, 2^155530231 is an apocalyptic number.

155530231 is a deficient number, since it is larger than the sum of its proper divisors (1).

155530231 is an equidigital number, since it uses as much as digits as its factorization.

155530231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2250, while the sum is 25.

The square root of 155530231 is about 12471.1760070973. The cubic root of 155530231 is about 537.7803618314.

Adding to 155530231 its reverse (132035551), we get a palindrome (287565782).

The spelling of 155530231 in words is "one hundred fifty-five million, five hundred thirty thousand, two hundred thirty-one".