1391640 has 32 divisors (see below), whose sum is σ = 4175280. Its totient is φ = 371072.

The previous prime is 1391629. The next prime is 1391641. The reversal of 1391640 is 461931.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 1391640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1391641) 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, 5679 + ... + 5918.

2^1391640 is an apocalyptic number.

1391640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1391640 is an abundant number, since it is smaller than the sum of its proper divisors (2783640).

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

1391640 is a wasteful number, since it uses less digits than its factorization.

1391640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11611 (or 11607 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 1391640 is about 1179.6779221465. The cubic root of 1391640 is about 111.6457771375.

The spelling of 1391640 in words is "one million, three hundred ninety-one thousand, six hundred forty".