778440 has 64 divisors (see below), whose sum is σ = 2520000. Its totient is φ = 191232.

The previous prime is 778439. The next prime is 778469. The reversal of 778440 is 44877.

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 = 778398 and 778407.

It is a congruent number.

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, 1311 + ... + 1809.

It is an arithmetic number, because the mean of its divisors is an integer number (39375).

2⁷⁷⁸⁴⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 778440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1260000).

778440 is an abundant number, since it is smaller than the sum of its proper divisors (1741560).

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

778440 is a wasteful number, since it uses less digits than its factorization.

778440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 526 (or 522 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 30.

The square root of 778440 is about 882.2924685160. The cubic root of 778440 is about 91.9902321073.

The spelling of 778440 in words is "seven hundred seventy-eight thousand, four hundred forty".