261631163 has 2 divisors, whose sum is σ = 261631164. Its totient is φ = 261631162.

The previous prime is 261631151. The next prime is 261631171. The reversal of 261631163 is 361136162.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261631163 - 2⁴ = 261631147 is a prime.

It is not a weakly prime, because it can be changed into another prime (261631133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130815581 + 130815582.

It is an arithmetic number, because the mean of its divisors is an integer number (130815582).

Almost surely, 2^261631163 is an apocalyptic number.

261631163 is a deficient number, since it is larger than the sum of its proper divisors (1).

261631163 is an equidigital number, since it uses as much as digits as its factorization.

261631163 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 29.

The square root of 261631163 is about 16175.0166305942. The cubic root of 261631163 is about 639.5823797298.

The spelling of 261631163 in words is "two hundred sixty-one million, six hundred thirty-one thousand, one hundred sixty-three".