66217172112 has 400 divisors, whose sum is σ = 237790113792. Its totient is φ = 17322439680.

The previous prime is 66217172111. The next prime is 66217172129. The reversal of 66217172112 is 21127171266.

66217172112 is a `hidden beast` number, since 6 + 621 + 7 + 1 + 7 + 21 + 1 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (66217172111) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 14975662 + ... + 14980082.

Almost surely, 2^66217172112 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66217172112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118895056896).

66217172112 is an abundant number, since it is smaller than the sum of its proper divisors (171572941680).

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

66217172112 is a wasteful number, since it uses less digits than its factorization.

66217172112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4588 (or 4573 counting only the distinct ones).

The product of its digits is 14112, while the sum is 36.

The spelling of 66217172112 in words is "sixty-six billion, two hundred seventeen million, one hundred seventy-two thousand, one hundred twelve".