1291268265 has 32 divisors (see below), whose sum is σ = 2437349376. Its totient is φ = 571250880.

The previous prime is 1291268261. The next prime is 1291268281. The reversal of 1291268265 is 5628621921.

It is not a de Polignac number, because 1291268265 - 2² = 1291268261 is a prime.

It is a super-2 number, since 2×1291268265² = 3334747464392220450, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1291268261) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 195097 + ... + 201606.

It is an arithmetic number, because the mean of its divisors is an integer number (76167168).

Almost surely, 2^1291268265 is an apocalyptic number.

1291268265 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1291268265 is a deficient number, since it is larger than the sum of its proper divisors (1146081111).

1291268265 is a wasteful number, since it uses less digits than its factorization.

1291268265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396749.

The product of its digits is 103680, while the sum is 42.

The square root of 1291268265 is about 35934.2213634858. The cubic root of 1291268265 is about 1088.9438652056.

The spelling of 1291268265 in words is "one billion, two hundred ninety-one million, two hundred sixty-eight thousand, two hundred sixty-five".