671778 has 12 divisors (see below), whose sum is σ = 1455558. Its totient is φ = 223920.

The previous prime is 671777. The next prime is 671779. The reversal of 671778 is 877176.

It is an interprime number because it is at equal distance from previous prime (671777) and next prime (671779).

It can be written as a sum of positive squares in only one way, i.e., 471969 + 199809 = 687^2 + 447^2 .

It is not an unprimeable number, because it can be changed into a prime (671777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18643 + ... + 18678.

2⁶⁷¹⁷⁷⁸ is an apocalyptic number.

671778 is an abundant number, since it is smaller than the sum of its proper divisors (783780).

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

671778 is a wasteful number, since it uses less digits than its factorization.

671778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37329 (or 37326 counting only the distinct ones).

The product of its digits is 16464, while the sum is 36.

The square root of 671778 is about 819.6206439567. The cubic root of 671778 is about 87.5807363659.

The spelling of 671778 in words is "six hundred seventy-one thousand, seven hundred seventy-eight".