1279495891 has 16 divisors (see below), whose sum is σ = 1397468160. Its totient is φ = 1166991840.

The previous prime is 1279495849. The next prime is 1279495901. The reversal of 1279495891 is 1985949721.

It is a cyclic number.

It is not a de Polignac number, because 1279495891 - 2⁹ = 1279495379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1279495391) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110520 + ... + 121546.

It is an arithmetic number, because the mean of its divisors is an integer number (87341760).

Almost surely, 2^1279495891 is an apocalyptic number.

1279495891 is a deficient number, since it is larger than the sum of its proper divisors (117972269).

1279495891 is a wasteful number, since it uses less digits than its factorization.

1279495891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11274.

The product of its digits is 1632960, while the sum is 55.

The square root of 1279495891 is about 35770.0418087539. The cubic root of 1279495891 is about 1085.6244901769.

The spelling of 1279495891 in words is "one billion, two hundred seventy-nine million, four hundred ninety-five thousand, eight hundred ninety-one".