671820 has 24 divisors (see below), whose sum is σ = 1881264. Its totient is φ = 179136.

The previous prime is 671791. The next prime is 671831. The reversal of 671820 is 28176.

It is a super-2 number, since 2×671820² = 902684224800, which contains 22 as substring.

It is an unprimeable number.

671820 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 7 ways as a sum of consecutive naturals, for example, 5539 + ... + 5658.

It is an arithmetic number, because the mean of its divisors is an integer number (78386).

2⁶⁷¹⁸²⁰ is an apocalyptic number.

671820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

671820 is an abundant number, since it is smaller than the sum of its proper divisors (1209444).

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

671820 is a wasteful number, since it uses less digits than its factorization.

671820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11209 (or 11207 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 671820 is about 819.6462651657. The cubic root of 671820 is about 87.5825615295.

Adding to 671820 its reverse (28176), we get a palindrome (699996).

The spelling of 671820 in words is "six hundred seventy-one thousand, eight hundred twenty".