671844581 has 2 divisors, whose sum is σ = 671844582. Its totient is φ = 671844580.

The previous prime is 671844469. The next prime is 671844587. The reversal of 671844581 is 185448176.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 668481025 + 3363556 = 25855^2 + 1834^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-671844581 is a prime.

It is a super-2 number, since 2×671844581² = 902750282038131122, which contains 22 as substring.

It is a Chen prime.

It is equal to p_34869086 and since 671844581 and 34869086 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671844587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335922290 + 335922291.

It is an arithmetic number, because the mean of its divisors is an integer number (335922291).

Almost surely, 2^671844581 is an apocalyptic number.

It is an amenable number.

671844581 is a deficient number, since it is larger than the sum of its proper divisors (1).

671844581 is an equidigital number, since it uses as much as digits as its factorization.

671844581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 215040, while the sum is 44.

The square root of 671844581 is about 25919.9649112417. The cubic root of 671844581 is about 875.8362969294.

The spelling of 671844581 in words is "six hundred seventy-one million, eight hundred forty-four thousand, five hundred eighty-one".