261937231 has 2 divisors, whose sum is σ = 261937232. Its totient is φ = 261937230.

The previous prime is 261937229. The next prime is 261937243. The reversal of 261937231 is 132739162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261937231 - 2¹ = 261937229 is a prime.

It is a super-2 number, since 2×261937231² = 137222225967894722, which contains 22 as substring.

Together with 261937229, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261937201) 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, 130968615 + 130968616.

It is an arithmetic number, because the mean of its divisors is an integer number (130968616).

Almost surely, 2^261937231 is an apocalyptic number.

261937231 is a deficient number, since it is larger than the sum of its proper divisors (1).

261937231 is an equidigital number, since it uses as much as digits as its factorization.

261937231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13608, while the sum is 34.

The square root of 261937231 is about 16184.4749992083. The cubic root of 261937231 is about 639.8316866963.

The spelling of 261937231 in words is "two hundred sixty-one million, nine hundred thirty-seven thousand, two hundred thirty-one".