1279639 has 4 divisors (see below), whose sum is σ = 1283040. Its totient is φ = 1276240.

The previous prime is 1279627. The next prime is 1279643. The reversal of 1279639 is 9369721.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9369721 = 3061².

It is a cyclic number.

It is not a de Polignac number, because 1279639 - 2⁷ = 1279511 is a prime.

It is a d-powerful number, because it can be written as 1 + 2¹⁵ + 7⁶ + 9⁶ + 6⁶ + 3⁹ + 9⁶ .

It is a Duffinian number.

1279639 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1279598 and 1279607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1279609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1054 + ... + 1915.

It is an arithmetic number, because the mean of its divisors is an integer number (320760).

2^1279639 is an apocalyptic number.

1279639 is a deficient number, since it is larger than the sum of its proper divisors (3401).

1279639 is an equidigital number, since it uses as much as digits as its factorization.

1279639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3400.

The product of its digits is 20412, while the sum is 37.

The square root of 1279639 is about 1131.2112976805. The cubic root of 1279639 is about 108.5664963628.

It can be divided in two parts, 1279 and 639, that multiplied together give a triangular number (817281 = T₁₂₇₈).

The spelling of 1279639 in words is "one million, two hundred seventy-nine thousand, six hundred thirty-nine".