66620556 has 30 divisors (see below), whose sum is σ = 174160140. Its totient is φ = 22206744.

The previous prime is 66620551. The next prime is 66620563. The reversal of 66620556 is 65502666.

66620556 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 66620556.

It is not an unprimeable number, because it can be changed into a prime (66620551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 102486 + ... + 103133.

It is an arithmetic number, because the mean of its divisors is an integer number (5805338).

Almost surely, 2^66620556 is an apocalyptic number.

It is an amenable number.

66620556 is an abundant number, since it is smaller than the sum of its proper divisors (107539584).

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

66620556 is a wasteful number, since it uses less digits than its factorization.

66620556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205635 (or 205624 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The square root of 66620556 is about 8162.1416307241. The cubic root of 66620556 is about 405.3866266804.

It can be divided in two parts, 66620 and 556, that added together give a palindrome (67176).

The spelling of 66620556 in words is "sixty-six million, six hundred twenty thousand, five hundred fifty-six".