681784 has 8 divisors (see below), whose sum is σ = 1278360. Its totient is φ = 340888.

The previous prime is 681781. The next prime is 681787. The reversal of 681784 is 487186.

It is a happy number.

681784 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 (681781) and next prime (681787).

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42604 + ... + 42619.

It is an arithmetic number, because the mean of its divisors is an integer number (159795).

2⁶⁸¹⁷⁸⁴ is an apocalyptic number.

It is an amenable number.

681784 is a deficient number, since it is larger than the sum of its proper divisors (596576).

681784 is a wasteful number, since it uses less digits than its factorization.

681784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85229 (or 85225 counting only the distinct ones).

The product of its digits is 10752, while the sum is 34.

The square root of 681784 is about 825.7021254666. The cubic root of 681784 is about 88.0134277031.

The spelling of 681784 in words is "six hundred eighty-one thousand, seven hundred eighty-four".