681998 has 4 divisors (see below), whose sum is σ = 1023000. Its totient is φ = 340998.

The previous prime is 681997. The next prime is 682001. The reversal of 681998 is 899186.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 170498 + ... + 170501.

It is an arithmetic number, because the mean of its divisors is an integer number (255750).

2⁶⁸¹⁹⁹⁸ is an apocalyptic number.

681998 is a deficient number, since it is larger than the sum of its proper divisors (341002).

681998 is a wasteful number, since it uses less digits than its factorization.

681998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341001.

The product of its digits is 31104, while the sum is 41.

The square root of 681998 is about 825.8317019829. The cubic root of 681998 is about 88.0226353618.

The spelling of 681998 in words is "six hundred eighty-one thousand, nine hundred ninety-eight".