1721071666 has 8 divisors (see below), whose sum is σ = 2617968384. Its totient is φ = 848415540.

The previous prime is 1721071663. The next prime is 1721071697. The reversal of 1721071666 is 6661701271.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (1721071663) 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, 6059970 + ... + 6060253.

It is an arithmetic number, because the mean of its divisors is an integer number (327246048).

Almost surely, 2^1721071666 is an apocalyptic number.

1721071666 is a deficient number, since it is larger than the sum of its proper divisors (896896718).

1721071666 is a wasteful number, since it uses less digits than its factorization.

1721071666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12120296.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 1721071666 is about 41485.8007756871. The cubic root of 1721071666 is about 1198.3940707663.

The spelling of 1721071666 in words is "one billion, seven hundred twenty-one million, seventy-one thousand, six hundred sixty-six".