666020666 has 4 divisors (see below), whose sum is σ = 999031002. Its totient is φ = 333010332.

The previous prime is 666020653. The next prime is 666020671.

666020666 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 568584025 + 97436641 = 23845^2 + 9871^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 166505165 + ... + 166505168.

Almost surely, 2^666020666 is an apocalyptic number.

666020666 is a deficient number, since it is larger than the sum of its proper divisors (333010336).

666020666 is a wasteful number, since it uses less digits than its factorization.

666020666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333010335.

The product of its (nonzero) digits is 93312, while the sum is 38.

The square root of 666020666 is about 25807.3761936389. The cubic root of 666020666 is about 873.2982067659.

The spelling of 666020666 in words is "six hundred sixty-six million, twenty thousand, six hundred sixty-six".