681987894 has 16 divisors (see below), whose sum is σ = 1558829568. Its totient is φ = 194853672.

The previous prime is 681987893. The next prime is 681987923. The reversal of 681987894 is 498789186.

681987894 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681987893) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8118862 + ... + 8118945.

It is an arithmetic number, because the mean of its divisors is an integer number (97426848).

Almost surely, 2^681987894 is an apocalyptic number.

681987894 is an abundant number, since it is smaller than the sum of its proper divisors (876841674).

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

681987894 is a wasteful number, since it uses less digits than its factorization.

681987894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16237819.

The product of its digits is 6967296, while the sum is 60.

The square root of 681987894 is about 26114.8979320234. The cubic root of 681987894 is about 880.2220057991. Note that the first 3 decimals are identical.

The spelling of 681987894 in words is "six hundred eighty-one million, nine hundred eighty-seven thousand, eight hundred ninety-four".