671998 has 4 divisors (see below), whose sum is σ = 1008000. Its totient is φ = 335998.

The previous prime is 671981. The next prime is 671999. The reversal of 671998 is 899176.

671998 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a Smith number, since the sum of its digits (40) 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 671998.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (671999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 167998 + ... + 168001.

It is an arithmetic number, because the mean of its divisors is an integer number (252000).

2⁶⁷¹⁹⁹⁸ is an apocalyptic number.

671998 is a deficient number, since it is larger than the sum of its proper divisors (336002).

671998 is a wasteful number, since it uses less digits than its factorization.

671998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336001.

The product of its digits is 27216, while the sum is 40.

The square root of 671998 is about 819.7548414008. The cubic root of 671998 is about 87.5902959025.

The spelling of 671998 in words is "six hundred seventy-one thousand, nine hundred ninety-eight".