1388320878 has 128 divisors (see below), whose sum is σ = 3446046720. Its totient is φ = 363916800.

The previous prime is 1388320867. The next prime is 1388320883. The reversal of 1388320878 is 8780238831.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 8517225 + ... + 8517387.

It is an arithmetic number, because the mean of its divisors is an integer number (26922240).

Almost surely, 2^1388320878 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1388320878, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1723023360).

1388320878 is an abundant number, since it is smaller than the sum of its proper divisors (2057725842).

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

1388320878 is a wasteful number, since it uses less digits than its factorization.

1388320878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422.

The product of its (nonzero) digits is 516096, while the sum is 48.

The square root of 1388320878 is about 37260.1781799282. The cubic root of 1388320878 is about 1115.5694646492.

The spelling of 1388320878 in words is "one billion, three hundred eighty-eight million, three hundred twenty thousand, eight hundred seventy-eight".