681859815 has 64 divisors (see below), whose sum is σ = 1374084096. Its totient is φ = 281014272.

The previous prime is 681859813. The next prime is 681859819. The reversal of 681859815 is 518958186.

681859815 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 681859815 - 2¹ = 681859813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681859811) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 52887 + ... + 64503.

It is an arithmetic number, because the mean of its divisors is an integer number (21470064).

Almost surely, 2^681859815 is an apocalyptic number.

681859815 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

681859815 is an abundant number, since it is smaller than the sum of its proper divisors (692224281).

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

681859815 is a wasteful number, since it uses less digits than its factorization.

681859815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11688.

The product of its digits is 691200, while the sum is 51.

The square root of 681859815 is about 26112.4455959223. The cubic root of 681859815 is about 880.1668997317.

The spelling of 681859815 in words is "six hundred eighty-one million, eight hundred fifty-nine thousand, eight hundred fifteen".