66491038080 has 256 divisors, whose sum is σ = 247884480000. Its totient is φ = 16797652992.

The previous prime is 66491038069. The next prime is 66491038111. The reversal of 66491038080 is 8083019466.

66491038080 is a `hidden beast` number, since 6 + 6 + 491 + 0 + 3 + 80 + 80 = 666.

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

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 31 ways as a sum of consecutive naturals, for example, 227061 + ... + 429579.

It is an arithmetic number, because the mean of its divisors is an integer number (968298750).

Almost surely, 2^66491038080 is an apocalyptic number.

66491038080 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 66491038080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123942240000).

66491038080 is an abundant number, since it is smaller than the sum of its proper divisors (181393441920).

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

66491038080 is a wasteful number, since it uses less digits than its factorization.

66491038080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202566 (or 202548 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The spelling of 66491038080 in words is "sixty-six billion, four hundred ninety-one million, thirty-eight thousand, eighty".