1265921291 has 4 divisors (see below), whose sum is σ = 1269678072. Its totient is φ = 1262164512.

The previous prime is 1265921273. The next prime is 1265921299. The reversal of 1265921291 is 1921295621.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1265921291 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1265921299) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1877885 + ... + 1878558.

It is an arithmetic number, because the mean of its divisors is an integer number (317419518).

Almost surely, 2^1265921291 is an apocalyptic number.

1265921291 is a deficient number, since it is larger than the sum of its proper divisors (3756781).

1265921291 is an equidigital number, since it uses as much as digits as its factorization.

1265921291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3756780.

The product of its digits is 19440, while the sum is 38.

The square root of 1265921291 is about 35579.7876750270. The cubic root of 1265921291 is about 1081.7715811331.

The spelling of 1265921291 in words is "one billion, two hundred sixty-five million, nine hundred twenty-one thousand, two hundred ninety-one".