66813073520 has 80 divisors (see below), whose sum is σ = 162151621632. Its totient is φ = 25554228480.

The previous prime is 66813073489. The next prime is 66813073531. The reversal of 66813073520 is 2537031866.

It is a tau number, because it is divible by the number of its divisors (80).

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 15 ways as a sum of consecutive naturals, for example, 7743929 + ... + 7752551.

Almost surely, 2^66813073520 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66813073520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81075810816).

66813073520 is an abundant number, since it is smaller than the sum of its proper divisors (95338548112).

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

66813073520 is a wasteful number, since it uses less digits than its factorization.

66813073520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12870 (or 12864 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 41.

The spelling of 66813073520 in words is "sixty-six billion, eight hundred thirteen million, seventy-three thousand, five hundred twenty".