66213656 has 16 divisors (see below), whose sum is σ = 124338240. Its totient is φ = 33056800.

The previous prime is 66213643. The next prime is 66213659. The reversal of 66213656 is 65631266.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66213659) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 296 + ... + 11511.

It is an arithmetic number, because the mean of its divisors is an integer number (7771140).

Almost surely, 2^66213656 is an apocalyptic number.

It is an amenable number.

66213656 is a deficient number, since it is larger than the sum of its proper divisors (58124584).

66213656 is a wasteful number, since it uses less digits than its factorization.

66213656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12514 (or 12510 counting only the distinct ones).

The product of its digits is 38880, while the sum is 35.

The square root of 66213656 is about 8137.1773975992. The cubic root of 66213656 is about 404.5596107199.

The spelling of 66213656 in words is "sixty-six million, two hundred thirteen thousand, six hundred fifty-six".