9781321671 has 64 divisors (see below), whose sum is σ = 17127728640. Its totient is φ = 5449489920.

The previous prime is 9781321651. The next prime is 9781321681. The reversal of 9781321671 is 1761231879.

9781321671 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 9781321671 - 2¹⁷ = 9781190599 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9781321601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 194581 + ... + 239633.

It is an arithmetic number, because the mean of its divisors is an integer number (267620760).

Almost surely, 2^9781321671 is an apocalyptic number.

9781321671 is a deficient number, since it is larger than the sum of its proper divisors (7346406969).

9781321671 is a wasteful number, since it uses less digits than its factorization.

9781321671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45133 (or 45127 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 9781321671 is about 98900.5645636060. The cubic root of 9781321671 is about 2138.6145333184.

The spelling of 9781321671 in words is "nine billion, seven hundred eighty-one million, three hundred twenty-one thousand, six hundred seventy-one".