681240 has 64 divisors (see below), whose sum is σ = 2338560. Its totient is φ = 155520.

The previous prime is 681229. The next prime is 681251. The reversal of 681240 is 42186.

It is an interprime number because it is at equal distance from previous prime (681229) and next prime (681251).

It is a Harshad number since it is a multiple of its sum of digits (21).

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, 435 + ... + 1245.

It is an arithmetic number, because the mean of its divisors is an integer number (36540).

2⁶⁸¹²⁴⁰ is an apocalyptic number.

681240 is a gapful number since it is divisible by the number (60) 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 681240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1169280).

681240 is an abundant number, since it is smaller than the sum of its proper divisors (1657320).

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

681240 is a wasteful number, since it uses less digits than its factorization.

681240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 832 (or 828 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 681240 is about 825.3726431134. The cubic root of 681240 is about 87.9900126407.

The spelling of 681240 in words is "six hundred eighty-one thousand, two hundred forty".