666166189623 has 16 divisors (see below), whose sum is σ = 968994143616. Its totient is φ = 403726609440.

The previous prime is 666166189621. The next prime is 666166189721. The reversal of 666166189623 is 326981661666.

It is a happy number.

It is not a de Polignac number, because 666166189623 - 2¹ = 666166189621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666166189621) 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, 1141536 + ... + 1623402.

It is an arithmetic number, because the mean of its divisors is an integer number (60562133976).

Almost surely, 2^666166189623 is an apocalyptic number.

666166189623 is a deficient number, since it is larger than the sum of its proper divisors (302827953993).

666166189623 is a wasteful number, since it uses less digits than its factorization.

666166189623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 523774.

The product of its digits is 20155392, while the sum is 60.

The spelling of 666166189623 in words is "six hundred sixty-six billion, one hundred sixty-six million, one hundred eighty-nine thousand, six hundred twenty-three".