666620673 has 4 divisors (see below), whose sum is σ = 888827568. Its totient is φ = 444413780.

The previous prime is 666620657. The next prime is 666620687. The reversal of 666620673 is 376026666.

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.

It is a cyclic number.

It is not a de Polignac number, because 666620673 - 2⁴ = 666620657 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (666620623) 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, 111103443 + ... + 111103448.

It is an arithmetic number, because the mean of its divisors is an integer number (222206892).

Almost surely, 2^666620673 is an apocalyptic number.

It is an amenable number.

666620673 is a deficient number, since it is larger than the sum of its proper divisors (222206895).

666620673 is a wasteful number, since it uses less digits than its factorization.

666620673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222206894.

The product of its (nonzero) digits is 326592, while the sum is 42.

The square root of 666620673 is about 25818.9982958286. The cubic root of 666620673 is about 873.5603746899.

The spelling of 666620673 in words is "six hundred sixty-six million, six hundred twenty thousand, six hundred seventy-three".