1666872723 has 16 divisors (see below), whose sum is σ = 2249782560. Its totient is φ = 1097631744.

The previous prime is 1666872709. The next prime is 1666872731. The reversal of 1666872723 is 3272786661.

It is not a de Polignac number, because 1666872723 - 2⁶ = 1666872659 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1666872703) 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 15 ways as a sum of consecutive naturals, for example, 315915 + ... + 321147.

It is an arithmetic number, because the mean of its divisors is an integer number (140611410).

Almost surely, 2^1666872723 is an apocalyptic number.

1666872723 is a deficient number, since it is larger than the sum of its proper divisors (582909837).

1666872723 is a wasteful number, since it uses less digits than its factorization.

1666872723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6518.

The product of its digits is 1016064, while the sum is 48.

The square root of 1666872723 is about 40827.3526327632. The cubic root of 1666872723 is about 1185.6799608427.

The spelling of 1666872723 in words is "one billion, six hundred sixty-six million, eight hundred seventy-two thousand, seven hundred twenty-three".