261634253 has 2 divisors, whose sum is σ = 261634254. Its totient is φ = 261634252.

The previous prime is 261634249. The next prime is 261634271. The reversal of 261634253 is 352436162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 242954569 + 18679684 = 15587^2 + 4322^2 .

It is a cyclic number.

It is not a de Polignac number, because 261634253 - 2² = 261634249 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261634213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130817126 + 130817127.

It is an arithmetic number, because the mean of its divisors is an integer number (130817127).

Almost surely, 2^261634253 is an apocalyptic number.

It is an amenable number.

261634253 is a deficient number, since it is larger than the sum of its proper divisors (1).

261634253 is an equidigital number, since it uses as much as digits as its factorization.

261634253 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25920, while the sum is 32.

The square root of 261634253 is about 16175.1121479883. The cubic root of 261634253 is about 639.5848976533.

The spelling of 261634253 in words is "two hundred sixty-one million, six hundred thirty-four thousand, two hundred fifty-three".