681895 has 4 divisors (see below), whose sum is σ = 818280. Its totient is φ = 545512.

The previous prime is 681883. The next prime is 681899. The reversal of 681895 is 598186.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-681895 is a prime.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681899) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68185 + ... + 68194.

It is an arithmetic number, because the mean of its divisors is an integer number (204570).

2⁶⁸¹⁸⁹⁵ is an apocalyptic number.

681895 is a deficient number, since it is larger than the sum of its proper divisors (136385).

681895 is a wasteful number, since it uses less digits than its factorization.

681895 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136384.

The product of its digits is 17280, while the sum is 37.

The square root of 681895 is about 825.7693382537. The cubic root of 681895 is about 88.0182038787.

The spelling of 681895 in words is "six hundred eighty-one thousand, eight hundred ninety-five".