66597220 has 12 divisors (see below), whose sum is σ = 139854204. Its totient is φ = 26638880.

The previous prime is 66597197. The next prime is 66597233. The reversal of 66597220 is 2279566.

66597220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 28132416 + 38464804 = 5304^2 + 6202^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 66597220.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1664911 + ... + 1664950.

It is an arithmetic number, because the mean of its divisors is an integer number (11654517).

Almost surely, 2^66597220 is an apocalyptic number.

It is an amenable number.

66597220 is an abundant number, since it is smaller than the sum of its proper divisors (73256984).

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

66597220 is a wasteful number, since it uses less digits than its factorization.

66597220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3329870 (or 3329868 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 37.

The square root of 66597220 is about 8160.7119787430. The cubic root of 66597220 is about 405.3392879026.

The spelling of 66597220 in words is "sixty-six million, five hundred ninety-seven thousand, two hundred twenty".