261791 has 2 divisors, whose sum is σ = 261792. Its totient is φ = 261790.

The previous prime is 261787. The next prime is 261799. The reversal of 261791 is 197162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261791 - 2² = 261787 is a prime.

It is equal to p₂₂₉₇₆ and since 261791 and 22976 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261791.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261799) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130895 + 130896.

It is an arithmetic number, because the mean of its divisors is an integer number (130896).

2²⁶¹⁷⁹¹ is an apocalyptic number.

261791 is a deficient number, since it is larger than the sum of its proper divisors (1).

261791 is an equidigital number, since it uses as much as digits as its factorization.

261791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 756, while the sum is 26.

The square root of 261791 is about 511.6551573081. The cubic root of 261791 is about 63.9712598822.

The spelling of 261791 in words is "two hundred sixty-one thousand, seven hundred ninety-one".