1279689 has 4 divisors (see below), whose sum is σ = 1706256. Its totient is φ = 853124.

The previous prime is 1279687. The next prime is 1279693. The reversal of 1279689 is 9869721.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1279689 - 2¹ = 1279687 is a prime.

It is a D-number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1279689.

It is not an unprimeable number, because it can be changed into a prime (1279687) 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, 213279 + ... + 213284.

It is an arithmetic number, because the mean of its divisors is an integer number (426564).

2^1279689 is an apocalyptic number.

It is an amenable number.

1279689 is a deficient number, since it is larger than the sum of its proper divisors (426567).

1279689 is an equidigital number, since it uses as much as digits as its factorization.

1279689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426566.

The product of its digits is 54432, while the sum is 42.

The square root of 1279689 is about 1131.2333976682. The cubic root of 1279689 is about 108.5679103694.

The spelling of 1279689 in words is "one million, two hundred seventy-nine thousand, six hundred eighty-nine".