66850542720 has 576 divisors, whose sum is σ = 257155025400. Its totient is φ = 15907553280.

The previous prime is 66850542713. The next prime is 66850542721. The reversal of 66850542720 is 2724505866.

66850542720 is a `hidden beast` number, since 6 + 6 + 85 + 0 + 542 + 7 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 20618662464 + 46231880256 = 143592^2 + 215016^2 .

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (66850542721) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 71959216 + ... + 71960144.

Almost surely, 2^66850542720 is an apocalyptic number.

66850542720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66850542720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128577512700).

66850542720 is an abundant number, since it is smaller than the sum of its proper divisors (190304482680).

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

66850542720 is a wasteful number, since it uses less digits than its factorization.

66850542720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1029 (or 983 counting only the distinct ones).

The product of its (nonzero) digits is 806400, while the sum is 45.

The spelling of 66850542720 in words is "sixty-six billion, eight hundred fifty million, five hundred forty-two thousand, seven hundred twenty".