181356431 has 2 divisors, whose sum is σ = 181356432. Its totient is φ = 181356430.

The previous prime is 181356319. The next prime is 181356433. The reversal of 181356431 is 134653181.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-181356431 is a prime.

It is a super-2 number, since 2×181356431² = 65780310130115522, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 181356433, 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 (181356433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90678215 + 90678216.

It is an arithmetic number, because the mean of its divisors is an integer number (90678216).

Almost surely, 2^181356431 is an apocalyptic number.

181356431 is a deficient number, since it is larger than the sum of its proper divisors (1).

181356431 is an equidigital number, since it uses as much as digits as its factorization.

181356431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 32.

The square root of 181356431 is about 13466.8641858452. The cubic root of 181356431 is about 566.0363478512.

The spelling of 181356431 in words is "one hundred eighty-one million, three hundred fifty-six thousand, four hundred thirty-one".