1291840 has 56 divisors (see below), whose sum is σ = 3364992. Its totient is φ = 468480.

The previous prime is 1291831. The next prime is 1291861. The reversal of 1291840 is 481921.

It is a happy number.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3337 + ... + 3703.

2^1291840 is an apocalyptic number.

1291840 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 1291840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1682496).

1291840 is an abundant number, since it is smaller than the sum of its proper divisors (2073152).

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

1291840 is a wasteful number, since it uses less digits than its factorization.

1291840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395 (or 385 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 1291840 is about 1136.5913953572. The cubic root of 1291840 is about 108.9104558758.

The spelling of 1291840 in words is "one million, two hundred ninety-one thousand, eight hundred forty".