671887649789 has 2 divisors, whose sum is σ = 671887649790. Its totient is φ = 671887649788.

The previous prime is 671887649749. The next prime is 671887649809. The reversal of 671887649789 is 987946788176.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 545832828025 + 126054821764 = 738805^2 + 355042^2 .

It is a cyclic number.

It is not a de Polignac number, because 671887649789 - 2²⁸ = 671619214333 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671887649749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335943824894 + 335943824895.

It is an arithmetic number, because the mean of its divisors is an integer number (335943824895).

Almost surely, 2^671887649789 is an apocalyptic number.

It is an amenable number.

671887649789 is a deficient number, since it is larger than the sum of its proper divisors (1).

671887649789 is an equidigital number, since it uses as much as digits as its factorization.

671887649789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2048385024, while the sum is 80.

The spelling of 671887649789 in words is "six hundred seventy-one billion, eight hundred eighty-seven million, six hundred forty-nine thousand, seven hundred eighty-nine".