66766393344 has 520 divisors, whose sum is σ = 217316010752. Its totient is φ = 18207866880.

The previous prime is 66766393321. The next prime is 66766393399. The reversal of 66766393344 is 44339366766.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 914608092 + ... + 914608164.

Almost surely, 2^66766393344 is an apocalyptic number.

66766393344 is a gapful number since it is divisible by the number (64) 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 66766393344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108658005376).

66766393344 is an abundant number, since it is smaller than the sum of its proper divisors (150549617408).

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

66766393344 is an frugal number, since it uses more digits than its factorization.

66766393344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159 (or 116 counting only the distinct ones).

The product of its digits is 35271936, while the sum is 57.

The spelling of 66766393344 in words is "sixty-six billion, seven hundred sixty-six million, three hundred ninety-three thousand, three hundred forty-four".