681816 has 16 divisors (see below), whose sum is σ = 1704600. Its totient is φ = 227264.

The previous prime is 681809. The next prime is 681823. The reversal of 681816 is 618186.

681816 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 (681809) and next prime (681823).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14181 + ... + 14228.

2⁶⁸¹⁸¹⁶ is an apocalyptic number.

It is an amenable number.

681816 is an abundant number, since it is smaller than the sum of its proper divisors (1022784).

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

681816 is a wasteful number, since it uses less digits than its factorization.

681816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28418 (or 28414 counting only the distinct ones).

The product of its digits is 2304, while the sum is 30.

The square root of 681816 is about 825.7215026872. The cubic root of 681816 is about 88.0148046717.

The spelling of 681816 in words is "six hundred eighty-one thousand, eight hundred sixteen".