66129220 has 12 divisors (see below), whose sum is σ = 138871404. Its totient is φ = 26451680.

The previous prime is 66129211. The next prime is 66129247. The reversal of 66129220 is 2292166.

It can be written as a sum of positive squares in 2 ways, for example, as 21399876 + 44729344 = 4626^2 + 6688^2 .

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, 1653211 + ... + 1653250.

It is an arithmetic number, because the mean of its divisors is an integer number (11572617).

Almost surely, 2^66129220 is an apocalyptic number.

It is an amenable number.

66129220 is an abundant number, since it is smaller than the sum of its proper divisors (72742184).

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

66129220 is a wasteful number, since it uses less digits than its factorization.

66129220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3306470 (or 3306468 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 66129220 is about 8131.9874569505. The cubic root of 66129220 is about 404.3875720614.

It can be divided in two parts, 66 and 129220, that added together give a triangular number (129286 = T₅₀₈).

The spelling of 66129220 in words is "sixty-six million, one hundred twenty-nine thousand, two hundred twenty".