671721729 has 16 divisors (see below), whose sum is σ = 1023994752. Its totient is φ = 383683968.

The previous prime is 671721727. The next prime is 671721761. The reversal of 671721729 is 927127176.

It is not a de Polignac number, because 671721729 - 2¹ = 671721727 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (671721727) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63397 + ... + 73229.

It is an arithmetic number, because the mean of its divisors is an integer number (63999672).

Almost surely, 2^671721729 is an apocalyptic number.

It is an amenable number.

671721729 is a deficient number, since it is larger than the sum of its proper divisors (352273023).

671721729 is a wasteful number, since it uses less digits than its factorization.

671721729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13096.

The product of its digits is 74088, while the sum is 42.

The square root of 671721729 is about 25917.5949694411. The cubic root of 671721729 is about 875.7829091852.

The spelling of 671721729 in words is "six hundred seventy-one million, seven hundred twenty-one thousand, seven hundred twenty-nine".