1666328073 has 4 divisors (see below), whose sum is σ = 2221770768. Its totient is φ = 1110885380.

The previous prime is 1666328057. The next prime is 1666328087. The reversal of 1666328073 is 3708236661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3708236661 = 3 ⋅1236078887.

It is a cyclic number.

It is not a de Polignac number, because 1666328073 - 2⁴ = 1666328057 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1666328093) 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, 277721343 + ... + 277721348.

It is an arithmetic number, because the mean of its divisors is an integer number (555442692).

Almost surely, 2^1666328073 is an apocalyptic number.

It is an amenable number.

1666328073 is a deficient number, since it is larger than the sum of its proper divisors (555442695).

1666328073 is an equidigital number, since it uses as much as digits as its factorization.

1666328073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555442694.

The product of its (nonzero) digits is 217728, while the sum is 42.

The square root of 1666328073 is about 40820.6819271800. The cubic root of 1666328073 is about 1185.5508066226.

The spelling of 1666328073 in words is "one billion, six hundred sixty-six million, three hundred twenty-eight thousand, seventy-three".