666989560 has 128 divisors (see below), whose sum is σ = 1662120000. Its totient is φ = 239755264.

The previous prime is 666989551. The next prime is 666989567. The reversal of 666989560 is 65989666.

666989560 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (55) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666989567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2938167 + ... + 2938393.

Almost surely, 2^666989560 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666989560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (831060000).

666989560 is an abundant number, since it is smaller than the sum of its proper divisors (995130440).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666989560 is a wasteful number, since it uses less digits than its factorization.

666989560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433 (or 429 counting only the distinct ones).

The product of its (nonzero) digits is 4199040, while the sum is 55.

The square root of 666989560 is about 25826.1410202918. The cubic root of 666989560 is about 873.7214786266.

The spelling of 666989560 in words is "six hundred sixty-six million, nine hundred eighty-nine thousand, five hundred sixty".