66689956 has 12 divisors (see below), whose sum is σ = 117560268. Its totient is φ = 33101312.

The previous prime is 66689939. The next prime is 66689957. The reversal of 66689956 is 65998666.

It can be written as a sum of positive squares in 2 ways, for example, as 39816100 + 26873856 = 6310^2 + 5184^2 .

It is a junction number, because it is equal to n+sod(n) for n = 66689897 and 66689906.

It is not an unprimeable number, because it can be changed into a prime (66689957) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60301 + ... + 61396.

It is an arithmetic number, because the mean of its divisors is an integer number (9796689).

Almost surely, 2^66689956 is an apocalyptic number.

It is an amenable number.

66689956 is a deficient number, since it is larger than the sum of its proper divisors (50870312).

66689956 is a wasteful number, since it uses less digits than its factorization.

66689956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121838 (or 121836 counting only the distinct ones).

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

The square root of 66689956 is about 8166.3918593220. The cubic root of 66689956 is about 405.5273443509.

The spelling of 66689956 in words is "sixty-six million, six hundred eighty-nine thousand, nine hundred fifty-six".