261166931 has 2 divisors, whose sum is σ = 261166932. Its totient is φ = 261166930.

The previous prime is 261166901. The next prime is 261166949. The reversal of 261166931 is 139661162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261166931 - 2¹⁰ = 261165907 is a prime.

It is a super-2 number, since 2×261166931² = 136416331695917522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 261166891 and 261166900.

It is not a weakly prime, because it can be changed into another prime (261166901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130583465 + 130583466.

It is an arithmetic number, because the mean of its divisors is an integer number (130583466).

Almost surely, 2^261166931 is an apocalyptic number.

261166931 is a deficient number, since it is larger than the sum of its proper divisors (1).

261166931 is an equidigital number, since it uses as much as digits as its factorization.

261166931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 35.

The square root of 261166931 is about 16160.6599803350. The cubic root of 261166931 is about 639.2038692727.

The spelling of 261166931 in words is "two hundred sixty-one million, one hundred sixty-six thousand, nine hundred thirty-one".