666001623 has 16 divisors (see below), whose sum is σ = 1068273920. Its totient is φ = 360542016.

The previous prime is 666001603. The next prime is 666001667. The reversal of 666001623 is 326100666.

It is not a de Polignac number, because 666001623 - 2¹⁴ = 665985239 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666001603) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 834190 + ... + 834987.

It is an arithmetic number, because the mean of its divisors is an integer number (66767120).

Almost surely, 2^666001623 is an apocalyptic number.

666001623 is a deficient number, since it is larger than the sum of its proper divisors (402272297).

666001623 is a wasteful number, since it uses less digits than its factorization.

666001623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1669206.

The product of its (nonzero) digits is 7776, while the sum is 30.

The square root of 666001623 is about 25807.0072460950. The cubic root of 666001623 is about 873.2898835126.

The spelling of 666001623 in words is "six hundred sixty-six million, one thousand, six hundred twenty-three".