66722220 has 36 divisors (see below), whose sum is σ = 202391280. Its totient is φ = 17792544.

The previous prime is 66722213. The next prime is 66722291. The reversal of 66722220 is 2222766.

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 185160 + ... + 185519.

It is an arithmetic number, because the mean of its divisors is an integer number (5621980).

Almost surely, 2^66722220 is an apocalyptic number.

66722220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66722220 is an abundant number, since it is smaller than the sum of its proper divisors (135669060).

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

66722220 is a wasteful number, since it uses less digits than its factorization.

66722220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370694 (or 370689 counting only the distinct ones).

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

The square root of 66722220 is about 8168.3670338691. The cubic root of 66722220 is about 405.5927306331.

Adding to 66722220 its reverse (2222766), we get a palindrome (68944986).

The spelling of 66722220 in words is "sixty-six million, seven hundred twenty-two thousand, two hundred twenty".