261493931 has 2 divisors, whose sum is σ = 261493932. Its totient is φ = 261493930.

The previous prime is 261493901. The next prime is 261493933. The reversal of 261493931 is 139394162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261493931 - 2⁶ = 261493867 is a prime.

It is a super-2 number, since 2×261493931² = 136758151899665522, which contains 22 as substring.

Together with 261493933, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (261493933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130746965 + 130746966.

It is an arithmetic number, because the mean of its divisors is an integer number (130746966).

Almost surely, 2^261493931 is an apocalyptic number.

261493931 is a deficient number, since it is larger than the sum of its proper divisors (1).

261493931 is an equidigital number, since it uses as much as digits as its factorization.

261493931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34992, while the sum is 38.

The square root of 261493931 is about 16170.7739765294. The cubic root of 261493931 is about 639.4705345930.

The spelling of 261493931 in words is "two hundred sixty-one million, four hundred ninety-three thousand, nine hundred thirty-one".