1279965121 has 4 divisors (see below), whose sum is σ = 1280650372. Its totient is φ = 1279279872.

The previous prime is 1279965109. The next prime is 1279965131. The reversal of 1279965121 is 1215699721.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1215699721 = 1523 ⋅798227.

It can be written as a sum of positive squares in 2 ways, for example, as 161798400 + 1118166721 = 12720^2 + 33439^2 .

It is a cyclic number.

It is not a de Polignac number, because 1279965121 - 2⁷ = 1279964993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1279965131) 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, 339816 + ... + 343561.

It is an arithmetic number, because the mean of its divisors is an integer number (320162593).

Almost surely, 2^1279965121 is an apocalyptic number.

It is an amenable number.

1279965121 is a deficient number, since it is larger than the sum of its proper divisors (685251).

1279965121 is an equidigital number, since it uses as much as digits as its factorization.

1279965121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 685250.

The product of its digits is 68040, while the sum is 43.

The square root of 1279965121 is about 35776.6001878323. The cubic root of 1279965121 is about 1085.7571844471.

The spelling of 1279965121 in words is "one billion, two hundred seventy-nine million, nine hundred sixty-five thousand, one hundred twenty-one".