840780 has 72 divisors (see below), whose sum is σ = 2660112. Its totient is φ = 222912.

The previous prime is 840767. The next prime is 840817. The reversal of 840780 is 87048.

It is a happy number.

It is a super-2 number, since 2×840780² = 1413822016800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

840780 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4774 + ... + 4946.

It is an arithmetic number, because the mean of its divisors is an integer number (36946).

2⁸⁴⁰⁷⁸⁰ 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 840780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1330056).

840780 is an abundant number, since it is smaller than the sum of its proper divisors (1819332).

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

840780 is a wasteful number, since it uses less digits than its factorization.

840780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197 (or 183 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 840780 is about 916.9405651404. The cubic root of 840780 is about 94.3830753437.

The spelling of 840780 in words is "eight hundred forty thousand, seven hundred eighty".