1391328378 has 48 divisors (see below), whose sum is σ = 3296603232. Its totient is φ = 420588000.

The previous prime is 1391328377. The next prime is 1391328403. The reversal of 1391328378 is 8738231931.

It is a happy number.

It is a super-2 number, since 2×1391328378² = 3871589310856221768, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1391328377) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 75013 + ... + 91703.

It is an arithmetic number, because the mean of its divisors is an integer number (68679234).

Almost surely, 2^1391328378 is an apocalyptic number.

1391328378 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1391328378, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1648301616).

1391328378 is an abundant number, since it is smaller than the sum of its proper divisors (1905274854).

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

1391328378 is a wasteful number, since it uses less digits than its factorization.

1391328378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17131 (or 17128 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The square root of 1391328378 is about 37300.5144468545. The cubic root of 1391328378 is about 1116.3744311487.

The spelling of 1391328378 in words is "one billion, three hundred ninety-one million, three hundred twenty-eight thousand, three hundred seventy-eight".