66212212 has 72 divisors (see below), whose sum is σ = 138636288. Its totient is φ = 27417600.

The previous prime is 66212189. The next prime is 66212213. The reversal of 66212212 is 21221266.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66212213) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 521293 + ... + 521419.

It is an arithmetic number, because the mean of its divisors is an integer number (1925504).

Almost surely, 2^66212212 is an apocalyptic number.

It is an amenable number.

66212212 is an abundant number, since it is smaller than the sum of its proper divisors (72424076).

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

66212212 is a wasteful number, since it uses less digits than its factorization.

66212212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217 (or 198 counting only the distinct ones).

The product of its digits is 576, while the sum is 22.

The square root of 66212212 is about 8137.0886685595. The cubic root of 66212212 is about 404.5566697942.

Adding to 66212212 its reverse (21221266), we get a palindrome (87433478).

The spelling of 66212212 in words is "sixty-six million, two hundred twelve thousand, two hundred twelve".