66851658720 has 960 divisors, whose sum is σ = 303776428032. Its totient is φ = 13436928000.

The previous prime is 66851658683. The next prime is 66851658733. The reversal of 66851658720 is 2785615866.

66851658720 is a `hidden beast` number, since 6 + 6 + 8 + 51 + 6 + 587 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 30934440 + ... + 30936600.

Almost surely, 2^66851658720 is an apocalyptic number.

66851658720 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 66851658720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (151888214016).

66851658720 is an abundant number, since it is smaller than the sum of its proper divisors (236924769312).

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

66851658720 is a wasteful number, since it uses less digits than its factorization.

66851658720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2237 (or 2220 counting only the distinct ones).

The product of its (nonzero) digits is 4838400, while the sum is 54.

The spelling of 66851658720 in words is "sixty-six billion, eight hundred fifty-one million, six hundred fifty-eight thousand, seven hundred twenty".