1279840 has 48 divisors (see below), whose sum is σ = 3190320. Its totient is φ = 483840.

The previous prime is 1279823. The next prime is 1279843. The reversal of 1279840 is 489721.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1279843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2830 + ... + 3250.

It is an arithmetic number, because the mean of its divisors is an integer number (66465).

2^1279840 is an apocalyptic number.

1279840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1279840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1595160).

1279840 is an abundant number, since it is smaller than the sum of its proper divisors (1910480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1279840 is a wasteful number, since it uses less digits than its factorization.

1279840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 455 (or 447 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 1279840 is about 1131.3001370105. The cubic root of 1279840 is about 108.5721804459.

It can be divided in two parts, 1 and 279840, that added together give a 4-th power (279841 = 23⁴).

The spelling of 1279840 in words is "one million, two hundred seventy-nine thousand, eight hundred forty".