261857147 has 2 divisors, whose sum is σ = 261857148. Its totient is φ = 261857146.

The previous prime is 261857111. The next prime is 261857161. The reversal of 261857147 is 741758162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261857147 - 2⁶ = 261857083 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (261857747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130928573 + 130928574.

It is an arithmetic number, because the mean of its divisors is an integer number (130928574).

Almost surely, 2^261857147 is an apocalyptic number.

261857147 is a deficient number, since it is larger than the sum of its proper divisors (1).

261857147 is an equidigital number, since it uses as much as digits as its factorization.

261857147 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 94080, while the sum is 41.

The square root of 261857147 is about 16182.0007106662. Note that the first 3 decimals coincide. The cubic root of 261857147 is about 639.7664732308.

The spelling of 261857147 in words is "two hundred sixty-one million, eight hundred fifty-seven thousand, one hundred forty-seven".