66212210 has 16 divisors (see below), whose sum is σ = 119525976. Its totient is φ = 26408448.

The previous prime is 66212189. The next prime is 66212213. The reversal of 66212210 is 1221266.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 53129521 + 13082689 = 7289^2 + 3617^2 .

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 7 ways as a sum of consecutive naturals, for example, 5849 + ... + 12908.

Almost surely, 2^66212210 is an apocalyptic number.

66212210 is a deficient number, since it is larger than the sum of its proper divisors (53313766).

66212210 is a wasteful number, since it uses less digits than its factorization.

66212210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19117.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 66212210 is about 8137.0885456655. The cubic root of 66212210 is about 404.5566657209.

Adding to 66212210 its reverse (1221266), we get a palindrome (67433476).

The spelling of 66212210 in words is "sixty-six million, two hundred twelve thousand, two hundred ten".