66734720640 has 768 divisors, whose sum is σ = 278014464000. Its totient is φ = 14980681728.

The previous prime is 66734720609. The next prime is 66734720671. The reversal of 66734720640 is 4602743766.

66734720640 is a `hidden beast` number, since 6 + 67 + 347 + 206 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (66734720609) and next prime (66734720671).

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

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 64229241 + ... + 64230279.

It is an arithmetic number, because the mean of its divisors is an integer number (361998000).

Almost surely, 2^66734720640 is an apocalyptic number.

66734720640 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 66734720640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139007232000).

66734720640 is an abundant number, since it is smaller than the sum of its proper divisors (211279743360).

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

66734720640 is a wasteful number, since it uses less digits than its factorization.

66734720640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1139 (or 1115 counting only the distinct ones).

The product of its (nonzero) digits is 1016064, while the sum is 45.

The spelling of 66734720640 in words is "sixty-six billion, seven hundred thirty-four million, seven hundred twenty thousand, six hundred forty".