671721087 has 4 divisors (see below), whose sum is σ = 895628120. Its totient is φ = 447814056.

The previous prime is 671721067. The next prime is 671721091. The reversal of 671721087 is 780127176.

671721087 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 671721087 - 2⁸ = 671720831 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (671721007) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111953512 + ... + 111953517.

It is an arithmetic number, because the mean of its divisors is an integer number (223907030).

Almost surely, 2^671721087 is an apocalyptic number.

671721087 is a deficient number, since it is larger than the sum of its proper divisors (223907033).

671721087 is a wasteful number, since it uses less digits than its factorization.

671721087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223907032.

The product of its (nonzero) digits is 32928, while the sum is 39.

The square root of 671721087 is about 25917.5825840297. The cubic root of 671721087 is about 875.7826301744.

The spelling of 671721087 in words is "six hundred seventy-one million, seven hundred twenty-one thousand, eighty-seven".