671748221 has 2 divisors, whose sum is σ = 671748222. Its totient is φ = 671748220.

The previous prime is 671748197. The next prime is 671748229. The reversal of 671748221 is 122847176.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 615288025 + 56460196 = 24805^2 + 7514^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-671748221 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671748229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335874110 + 335874111.

It is an arithmetic number, because the mean of its divisors is an integer number (335874111).

Almost surely, 2^671748221 is an apocalyptic number.

It is an amenable number.

671748221 is a deficient number, since it is larger than the sum of its proper divisors (1).

671748221 is an equidigital number, since it uses as much as digits as its factorization.

671748221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 37632, while the sum is 38.

The square root of 671748221 is about 25918.1060457743. The cubic root of 671748221 is about 875.7944223535.

The spelling of 671748221 in words is "six hundred seventy-one million, seven hundred forty-eight thousand, two hundred twenty-one".