66213286617578 has 4 divisors (see below), whose sum is σ = 99319929926370. Its totient is φ = 33106643308788.

The previous prime is 66213286617529. The next prime is 66213286617581. The reversal of 66213286617578 is 87571668231266.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 58087064091169 + 8126222526409 = 7621487^2 + 2850653^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16553321654393 + ... + 16553321654396.

Almost surely, 2^{66213286617578} is an apocalyptic number.

66213286617578 is a deficient number, since it is larger than the sum of its proper divisors (33106643308792).

66213286617578 is a wasteful number, since it uses less digits than its factorization.

66213286617578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33106643308791.

The product of its digits is 243855360, while the sum is 68.

The spelling of 66213286617578 in words is "sixty-six trillion, two hundred thirteen billion, two hundred eighty-six million, six hundred seventeen thousand, five hundred seventy-eight".