66664556 has 12 divisors (see below), whose sum is σ = 133329168. Its totient is φ = 28570512.

The previous prime is 66664547. The next prime is 66664561. The reversal of 66664556 is 65546666.

66664556 is an admirable number.

It is a hoax number, since the sum of its digits (44) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1190411 + ... + 1190466.

It is an arithmetic number, because the mean of its divisors is an integer number (11110764).

Almost surely, 2^66664556 is an apocalyptic number.

It is an amenable number.

66664556 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

66664556 is a wasteful number, since it uses less digits than its factorization.

66664556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2380888 (or 2380886 counting only the distinct ones).

The product of its digits is 777600, while the sum is 44.

The square root of 66664556 is about 8164.8365568455. The cubic root of 66664556 is about 405.4758538261.

The spelling of 66664556 in words is "sixty-six million, six hundred sixty-four thousand, five hundred fifty-six".