1666722001 has 8 divisors (see below), whose sum is σ = 1923319424. Its totient is φ = 1414748160.

The previous prime is 1666721999. The next prime is 1666722053. The reversal of 1666722001 is 1002276661.

It is a happy number.

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

It is not a de Polignac number, because 1666722001 - 2¹ = 1666721999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666722401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1155120 + ... + 1156561.

It is an arithmetic number, because the mean of its divisors is an integer number (240414928).

Almost surely, 2^1666722001 is an apocalyptic number.

It is an amenable number.

1666722001 is a deficient number, since it is larger than the sum of its proper divisors (256597423).

1666722001 is a wasteful number, since it uses less digits than its factorization.

1666722001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2311791.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 1666722001 is about 40825.5067451710. The cubic root of 1666722001 is about 1185.6442225728.

Adding to 1666722001 its reverse (1002276661), we get a palindrome (2668998662).

The spelling of 1666722001 in words is "one billion, six hundred sixty-six million, seven hundred twenty-two thousand, one".