66656620 has 12 divisors (see below), whose sum is σ = 139978944. Its totient is φ = 26662640.

The previous prime is 66656593. The next prime is 66656651. The reversal of 66656620 is 2665666.

It is a self number, because there is not a number n which added to its sum of digits gives 66656620.

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, 1666396 + ... + 1666435.

It is an arithmetic number, because the mean of its divisors is an integer number (11664912).

Almost surely, 2^66656620 is an apocalyptic number.

It is an amenable number.

66656620 is an abundant number, since it is smaller than the sum of its proper divisors (73322324).

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

66656620 is a wasteful number, since it uses less digits than its factorization.

66656620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3332840 (or 3332838 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 37.

The square root of 66656620 is about 8164.3505559230. The cubic root of 66656620 is about 405.4597633963.

It can be divided in two parts, 66656 and 620, that added together give a palindrome (67276).

The spelling of 66656620 in words is "sixty-six million, six hundred fifty-six thousand, six hundred twenty".