261099257 has 2 divisors, whose sum is σ = 261099258. Its totient is φ = 261099256.

The previous prime is 261099217. The next prime is 261099281. The reversal of 261099257 is 752990162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 256672441 + 4426816 = 16021^2 + 2104^2 .

It is a cyclic number.

It is not a de Polignac number, because 261099257 - 2²⁴ = 244322041 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (261099217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130549628 + 130549629.

It is an arithmetic number, because the mean of its divisors is an integer number (130549629).

Almost surely, 2^261099257 is an apocalyptic number.

It is an amenable number.

261099257 is a deficient number, since it is larger than the sum of its proper divisors (1).

261099257 is an equidigital number, since it uses as much as digits as its factorization.

261099257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 68040, while the sum is 41.

The square root of 261099257 is about 16158.5660564296. The cubic root of 261099257 is about 639.1486539878.

The spelling of 261099257 in words is "two hundred sixty-one million, ninety-nine thousand, two hundred fifty-seven".