666906989 has 8 divisors (see below), whose sum is σ = 766391808. Its totient is φ = 568475280.

The previous prime is 666906967. The next prime is 666907001. The reversal of 666906989 is 989609666.

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

It is a cyclic number.

It is not a de Polignac number, because 666906989 - 2⁸ = 666906733 is a prime.

It is a super-2 number, since 2×666906989² = 889529863954092242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666906949) 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, 261917 + ... + 264450.

It is an arithmetic number, because the mean of its divisors is an integer number (95798976).

Almost surely, 2^666906989 is an apocalyptic number.

It is an amenable number.

666906989 is a deficient number, since it is larger than the sum of its proper divisors (99484819).

666906989 is a wasteful number, since it uses less digits than its factorization.

666906989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526555.

The product of its (nonzero) digits is 7558272, while the sum is 59.

The square root of 666906989 is about 25824.5423773588. The cubic root of 666906989 is about 873.6854225733.

The spelling of 666906989 in words is "six hundred sixty-six million, nine hundred six thousand, nine hundred eighty-nine".