265518991 has 2 divisors, whose sum is σ = 265518992. Its totient is φ = 265518990.

The previous prime is 265518989. The next prime is 265519003. The reversal of 265518991 is 199815562.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 265518991 - 2¹ = 265518989 is a prime.

Together with 265518989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (265518961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 132759495 + 132759496.

It is an arithmetic number, because the mean of its divisors is an integer number (132759496).

Almost surely, 2^265518991 is an apocalyptic number.

265518991 is a deficient number, since it is larger than the sum of its proper divisors (1).

265518991 is an equidigital number, since it uses as much as digits as its factorization.

265518991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 194400, while the sum is 46.

The square root of 265518991 is about 16294.7534807987. The cubic root of 265518991 is about 642.7348713086.

The spelling of 265518991 in words is "two hundred sixty-five million, five hundred eighteen thousand, nine hundred ninety-one".