681819 has 16 divisors (see below), whose sum is σ = 997920. Its totient is φ = 412160.

The previous prime is 681809. The next prime is 681823. The reversal of 681819 is 918186.

It is a cyclic number.

It is not a de Polignac number, because 681819 - 2⁵ = 681787 is a prime.

It is a super-2 number, since 2×681819² = 929754297522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 681819.

It is not an unprimeable number, because it can be changed into a prime (681809) 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, 1249 + ... + 1709.

It is an arithmetic number, because the mean of its divisors is an integer number (62370).

2⁶⁸¹⁸¹⁹ is an apocalyptic number.

681819 is a deficient number, since it is larger than the sum of its proper divisors (316101).

681819 is a wasteful number, since it uses less digits than its factorization.

681819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 510.

The product of its digits is 3456, while the sum is 33.

The square root of 681819 is about 825.7233192783. The cubic root of 681819 is about 88.0149337603.

The spelling of 681819 in words is "six hundred eighty-one thousand, eight hundred nineteen".