1397640 has 64 divisors (see below), whose sum is σ = 4420800. Its totient is φ = 352512.

The previous prime is 1397633. The next prime is 1397657. The reversal of 1397640 is 467931.

It is a happy number.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1397598 and 1397607.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1974 + ... + 2586.

It is an arithmetic number, because the mean of its divisors is an integer number (69075).

2^1397640 is an apocalyptic number.

1397640 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 1397640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2210400).

1397640 is an abundant number, since it is smaller than the sum of its proper divisors (3023160).

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

1397640 is a wasteful number, since it uses less digits than its factorization.

1397640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 646 (or 642 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 30.

The square root of 1397640 is about 1182.2182539616. The cubic root of 1397640 is about 111.8059991895.

The spelling of 1397640 in words is "one million, three hundred ninety-seven thousand, six hundred forty".