66399913080 has 256 divisors, whose sum is σ = 241914470400. Its totient is φ = 16127354880.

The previous prime is 66399913067. The next prime is 66399913081. The reversal of 66399913080 is 8031999366.

66399913080 is a `hidden beast` number, since 66 + 399 + 91 + 30 + 80 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66399913081) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 510829 + ... + 627491.

It is an arithmetic number, because the mean of its divisors is an integer number (944978400).

Almost surely, 2^66399913080 is an apocalyptic number.

66399913080 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 66399913080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120957235200).

66399913080 is an abundant number, since it is smaller than the sum of its proper divisors (175514557320).

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

66399913080 is a wasteful number, since it uses less digits than its factorization.

66399913080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116731 (or 116721 counting only the distinct ones).

The product of its (nonzero) digits is 1889568, while the sum is 54.

The spelling of 66399913080 in words is "sixty-six billion, three hundred ninety-nine million, nine hundred thirteen thousand, eighty".