66251672064 has 320 divisors, whose sum is σ = 206384112000. Its totient is φ = 20953497600.

The previous prime is 66251672029. The next prime is 66251672083. The reversal of 66251672064 is 46027615266.

66251672064 is a `hidden beast` number, since 6 + 6 + 2 + 516 + 72 + 0 + 64 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23651464 + ... + 23654264.

It is an arithmetic number, because the mean of its divisors is an integer number (644950350).

Almost surely, 2^66251672064 is an apocalyptic number.

66251672064 is a gapful number since it is divisible by the number (64) 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 66251672064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103192056000).

66251672064 is an abundant number, since it is smaller than the sum of its proper divisors (140132439936).

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

66251672064 is a wasteful number, since it uses less digits than its factorization.

66251672064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2916 (or 2894 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The spelling of 66251672064 in words is "sixty-six billion, two hundred fifty-one million, six hundred seventy-two thousand, sixty-four".