671978 has 8 divisors (see below), whose sum is σ = 1011972. Its totient is φ = 334656.

The previous prime is 671971. The next prime is 671981. The reversal of 671978 is 879176.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 667489 + 4489 = 817^2 + 67^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (671971) by changing a digit.

671978 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 176 + ... + 1172.

2⁶⁷¹⁹⁷⁸ is an apocalyptic number.

671978 is a deficient number, since it is larger than the sum of its proper divisors (339994).

671978 is a wasteful number, since it uses less digits than its factorization.

671978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1336.

The product of its digits is 21168, while the sum is 38.

The square root of 671978 is about 819.7426425409. The cubic root of 671978 is about 87.5894269399.

The spelling of 671978 in words is "six hundred seventy-one thousand, nine hundred seventy-eight".