780640 has 96 divisors (see below), whose sum is σ = 2286144. Its totient is φ = 245760.

The previous prime is 780631. The next prime is 780649. The reversal of 780640 is 46087.

780640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (780631) and next prime (780649).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (780649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19020 + ... + 19060.

It is an arithmetic number, because the mean of its divisors is an integer number (23814).

2⁷⁸⁰⁶⁴⁰ is an apocalyptic number.

780640 is a gapful number since it is divisible by the number (70) 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 780640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1143072).

780640 is an abundant number, since it is smaller than the sum of its proper divisors (1505504).

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

780640 is a wasteful number, since it uses less digits than its factorization.

780640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80 (or 72 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 780640 is about 883.5383409904. The cubic root of 780640 is about 92.0768104596.

The spelling of 780640 in words is "seven hundred eighty thousand, six hundred forty".