1390840 has 64 divisors (see below), whose sum is σ = 3564000. Its totient is φ = 483840.

The previous prime is 1390813. The next prime is 1390841. The reversal of 1390840 is 480931.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1390841) 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 15 ways as a sum of consecutive naturals, for example, 12706 + ... + 12814.

2^1390840 is an apocalyptic number.

1390840 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 1390840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1782000).

1390840 is an abundant number, since it is smaller than the sum of its proper divisors (2173160).

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

1390840 is a wasteful number, since it uses less digits than its factorization.

1390840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160 (or 156 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 1390840 is about 1179.3387978015. The cubic root of 1390840 is about 111.6243794239.

Subtracting from 1390840 its reverse (480931), we obtain a palindrome (909909).

The spelling of 1390840 in words is "one million, three hundred ninety thousand, eight hundred forty".