66222720 has 96 divisors (see below), whose sum is σ = 228695220. Its totient is φ = 17657856.

The previous prime is 66222707. The next prime is 66222781. The reversal of 66222720 is 2722266.

66222720 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 66194496 + 28224 = 8136^2 + 168^2 .

It is a tau number, because it is divible by the number of its divisors (96).

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 11 ways as a sum of consecutive naturals, for example, 12 + ... + 11508.

Almost surely, 2^66222720 is an apocalyptic number.

66222720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66222720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114347610).

66222720 is an abundant number, since it is smaller than the sum of its proper divisors (162472500).

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

66222720 is a wasteful number, since it uses less digits than its factorization.

66222720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11522 (or 11507 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 66222720 is about 8137.7343284234. The cubic root of 66222720 is about 404.5780699584.

Adding to 66222720 its reverse (2722266), we get a palindrome (68944986).

The spelling of 66222720 in words is "sixty-six million, two hundred twenty-two thousand, seven hundred twenty".