666642066 has 16 divisors (see below), whose sum is σ = 1338475104. Its totient is φ = 221348864.

The previous prime is 666642047. The next prime is 666642071. The reversal of 666642066 is 660246666.

It is a happy number.

666642066 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×666642066³ (a number of 27 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 214620 + ... + 217703.

It is an arithmetic number, because the mean of its divisors is an integer number (83654694).

Almost surely, 2^666642066 is an apocalyptic number.

666642066 is an abundant number, since it is smaller than the sum of its proper divisors (671833038).

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

666642066 is a wasteful number, since it uses less digits than its factorization.

666642066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432585.

The product of its (nonzero) digits is 373248, while the sum is 42.

The square root of 666642066 is about 25819.4125804597. The cubic root of 666642066 is about 873.5697192732.

The spelling of 666642066 in words is "six hundred sixty-six million, six hundred forty-two thousand, sixty-six".