261800057 has 2 divisors, whose sum is σ = 261800058. Its totient is φ = 261800056.

The previous prime is 261800041. The next prime is 261800059. The reversal of 261800057 is 750008162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 229492201 + 32307856 = 15149^2 + 5684^2 .

It is a cyclic number.

It is not a de Polignac number, because 261800057 - 2⁴ = 261800041 is a prime.

Together with 261800059, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (261800059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130900028 + 130900029.

It is an arithmetic number, because the mean of its divisors is an integer number (130900029).

Almost surely, 2^261800057 is an apocalyptic number.

It is an amenable number.

261800057 is a deficient number, since it is larger than the sum of its proper divisors (1).

261800057 is an equidigital number, since it uses as much as digits as its factorization.

261800057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 261800057 is about 16180.2366175529. The cubic root of 261800057 is about 639.7199759669.

The spelling of 261800057 in words is "two hundred sixty-one million, eight hundred thousand, fifty-seven".