671988161 has 16 divisors (see below), whose sum is σ = 737998800. Its totient is φ = 608145408.

The previous prime is 671988157. The next prime is 671988167. The reversal of 671988161 is 161889176.

It can be written as a sum of positive squares in 8 ways, for example, as 193600 + 671794561 = 440^2 + 25919^2 .

It is not a de Polignac number, because 671988161 - 2² = 671988157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (671988167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 135005 + ... + 139893.

It is an arithmetic number, because the mean of its divisors is an integer number (46124925).

Almost surely, 2^671988161 is an apocalyptic number.

It is an amenable number.

671988161 is a deficient number, since it is larger than the sum of its proper divisors (66010639).

671988161 is a wasteful number, since it uses less digits than its factorization.

671988161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5108.

The product of its digits is 145152, while the sum is 47.

The square root of 671988161 is about 25922.7344429557. The cubic root of 671988161 is about 875.8986841848.

The spelling of 671988161 in words is "six hundred seventy-one million, nine hundred eighty-eight thousand, one hundred sixty-one".