66666663 has 24 divisors (see below), whose sum is σ = 110386848. Its totient is φ = 37979712.

The previous prime is 66666653. The next prime is 66666667. The reversal of 66666663 is 36666666.

It is not a de Polignac number, because 66666663 - 2⁵ = 66666631 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66666667) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22081 + ... + 24917.

It is an arithmetic number, because the mean of its divisors is an integer number (4599452).

Almost surely, 2^66666663 is an apocalyptic number.

66666663 is a gapful number since it is divisible by the number (63) formed by its first and last digit.

66666663 is a deficient number, since it is larger than the sum of its proper divisors (43720185).

66666663 is a wasteful number, since it uses less digits than its factorization.

66666663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3223 (or 3220 counting only the distinct ones).

The product of its digits is 839808, while the sum is 45.

The square root of 66666663 is about 8164.9655847407. The cubic root of 66666663 is about 405.4801256044.

The spelling of 66666663 in words is "sixty-six million, six hundred sixty-six thousand, six hundred sixty-three".