66764528640 has 880 divisors, whose sum is σ = 259774125600. Its totient is φ = 16339304448.

The previous prime is 66764528629. The next prime is 66764528647. The reversal of 66764528640 is 4682546766.

66764528640 is a `hidden beast` number, since 6 + 6 + 76 + 4 + 528 + 6 + 40 = 666.

66764528640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 (66764528647) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 291548046 + ... + 291548274.

It is an arithmetic number, because the mean of its divisors is an integer number (295197870).

Almost surely, 2^66764528640 is an apocalyptic number.

66764528640 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 66764528640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129887062800).

66764528640 is an abundant number, since it is smaller than the sum of its proper divisors (193009596960).

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

66764528640 is a wasteful number, since it uses less digits than its factorization.

66764528640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322 (or 295 counting only the distinct ones).

The product of its (nonzero) digits is 11612160, while the sum is 54.

The spelling of 66764528640 in words is "sixty-six billion, seven hundred sixty-four million, five hundred twenty-eight thousand, six hundred forty".