265985591 has 2 divisors, whose sum is σ = 265985592. Its totient is φ = 265985590.

The previous prime is 265985567. The next prime is 265985627. The reversal of 265985591 is 195589562.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 265985591 - 2⁶ = 265985527 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (265985521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 132992795 + 132992796.

It is an arithmetic number, because the mean of its divisors is an integer number (132992796).

Almost surely, 2^265985591 is an apocalyptic number.

265985591 is a deficient number, since it is larger than the sum of its proper divisors (1).

265985591 is an equidigital number, since it uses as much as digits as its factorization.

265985591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 972000, while the sum is 50.

The square root of 265985591 is about 16309.0646880807. The cubic root of 265985591 is about 643.1111464523. Note that the first 4 decimals are identical.

The spelling of 265985591 in words is "two hundred sixty-five million, nine hundred eighty-five thousand, five hundred ninety-one".