66212220 has 48 divisors (see below), whose sum is σ = 191792160. Its totient is φ = 17047296.

The previous prime is 66212213. The next prime is 66212227. The reversal of 66212220 is 2221266.

It is an interprime number because it is at equal distance from previous prime (66212213) and next prime (66212227).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66212227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17287 + ... + 20766.

It is an arithmetic number, because the mean of its divisors is an integer number (3995670).

Almost surely, 2^66212220 is an apocalyptic number.

66212220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66212220 is an abundant number, since it is smaller than the sum of its proper divisors (125579940).

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

66212220 is a wasteful number, since it uses less digits than its factorization.

66212220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38094 (or 38092 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 66212220 is about 8137.0891601358. The cubic root of 66212220 is about 404.5566860876.

Adding to 66212220 its reverse (2221266), we get a palindrome (68433486).

The spelling of 66212220 in words is "sixty-six million, two hundred twelve thousand, two hundred twenty".