1265081391 has 24 divisors (see below), whose sum is σ = 2093690144. Its totient is φ = 721068480.

The previous prime is 1265081369. The next prime is 1265081429. The reversal of 1265081391 is 1931805621.

1265081391 is a `hidden beast` number, since 1 + 265 + 0 + 8 + 1 + 391 = 666.

It is not a de Polignac number, because 1265081391 - 2¹⁸ = 1264819247 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265081791) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 280 + ... + 50301.

Almost surely, 2^1265081391 is an apocalyptic number.

1265081391 is a deficient number, since it is larger than the sum of its proper divisors (828608753).

1265081391 is a wasteful number, since it uses less digits than its factorization.

1265081391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50991 (or 50988 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 1265081391 is about 35567.9826669998. The cubic root of 1265081391 is about 1081.5322874345.

The spelling of 1265081391 in words is "one billion, two hundred sixty-five million, eighty-one thousand, three hundred ninety-one".