1391840 has 24 divisors (see below), whose sum is σ = 3288600. Its totient is φ = 556672.

The previous prime is 1391779. The next prime is 1391849. The reversal of 1391840 is 481931.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1391849) 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, 4190 + ... + 4509.

It is an arithmetic number, because the mean of its divisors is an integer number (137025).

2^1391840 is an apocalyptic number.

1391840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1391840 is an abundant number, since it is smaller than the sum of its proper divisors (1896760).

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

1391840 is an equidigital number, since it uses as much as digits as its factorization.

1391840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8714 (or 8706 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 1391840 is about 1179.7626880013. The cubic root of 1391840 is about 111.6511252844.

Subtracting from 1391840 its reverse (481931), we obtain a palindrome (909909).

The spelling of 1391840 in words is "one million, three hundred ninety-one thousand, eight hundred forty".