666989983 has 8 divisors (see below), whose sum is σ = 728153856. Its totient is φ = 605914200.

The previous prime is 666989963. The next prime is 666990031. The reversal of 666989983 is 389989666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666989983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666989963) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5653 + ... + 36958.

It is an arithmetic number, because the mean of its divisors is an integer number (91019232).

Almost surely, 2^666989983 is an apocalyptic number.

666989983 is a deficient number, since it is larger than the sum of its proper divisors (61163873).

666989983 is a wasteful number, since it uses less digits than its factorization.

666989983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44045.

The product of its digits is 30233088, while the sum is 64.

The square root of 666989983 is about 25826.1492096673. The cubic root of 666989983 is about 873.7216633292.

The spelling of 666989983 in words is "six hundred sixty-six million, nine hundred eighty-nine thousand, nine hundred eighty-three".