1378640 has 40 divisors (see below), whose sum is σ = 3377760. Its totient is φ = 521856.

The previous prime is 1378639. The next prime is 1378669. The reversal of 1378640 is 468731.

1378640 = T₉₅ + T₉₆ + ... + T₂₀₈.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1067 + ... + 1973.

It is an arithmetic number, because the mean of its divisors is an integer number (84444).

2^1378640 is an apocalyptic number.

1378640 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 1378640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1688880).

1378640 is an abundant number, since it is smaller than the sum of its proper divisors (1999120).

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

1378640 is a wasteful number, since it uses less digits than its factorization.

1378640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 939 (or 933 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 1378640 is about 1174.1550153195. The cubic root of 1378640 is about 111.2970427653.

Subtracting from 1378640 its reverse (468731), we obtain a palindrome (909909).

The spelling of 1378640 in words is "one million, three hundred seventy-eight thousand, six hundred forty".