66609213 has 32 divisors (see below), whose sum is σ = 105390720. Its totient is φ = 36956160.

The previous prime is 66609209. The next prime is 66609223. The reversal of 66609213 is 31290666.

It is a happy number.

It is not a de Polignac number, because 66609213 - 2² = 66609209 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66609203) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19153 + ... + 22361.

It is an arithmetic number, because the mean of its divisors is an integer number (3293460).

Almost surely, 2^66609213 is an apocalyptic number.

It is an amenable number.

66609213 is a deficient number, since it is larger than the sum of its proper divisors (38781507).

66609213 is a wasteful number, since it uses less digits than its factorization.

66609213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3277.

The product of its (nonzero) digits is 11664, while the sum is 33.

The square root of 66609213 is about 8161.4467467478. The cubic root of 66609213 is about 405.3636179587.

Adding to 66609213 its reverse (31290666), we get a palindrome (97899879).

The spelling of 66609213 in words is "sixty-six million, six hundred nine thousand, two hundred thirteen".