66005072640 has 540 divisors, whose sum is σ = 255811170384. Its totient is φ = 16243089408.

The previous prime is 66005072599. The next prime is 66005072659. The reversal of 66005072640 is 4627050066.

66005072640 is a `hidden beast` number, since 6 + 6 + 0 + 0 + 5 + 0 + 7 + 2 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (540).

It is a super-2 number, since 2×66005072640² (a number of 22 digits) contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 66005072595 and 66005072604.

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 59 ways as a sum of consecutive naturals, for example, 17520037 + ... + 17523803.

Almost surely, 2^66005072640 is an apocalyptic number.

66005072640 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 66005072640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127905585192).

66005072640 is an abundant number, since it is smaller than the sum of its proper divisors (189806097744).

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

66005072640 is a wasteful number, since it uses less digits than its factorization.

66005072640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3826 (or 3790 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The spelling of 66005072640 in words is "sixty-six billion, five million, seventy-two thousand, six hundred forty".