66739510656 has 1536 divisors, whose sum is σ = 276945177600. Its totient is φ = 15479341056.

The previous prime is 66739510631. The next prime is 66739510657. The reversal of 66739510656 is 65601593766.

66739510656 is a `hidden beast` number, since 6 + 6 + 73 + 9 + 510 + 6 + 56 = 666.

66739510656 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×66739510656³ (a number of 33 digits) contains 333 as substring.

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 (66739510657) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 914239836 + ... + 914239908.

It is an arithmetic number, because the mean of its divisors is an integer number (180302850).

Almost surely, 2^66739510656 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 66739510656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138472588800).

66739510656 is an abundant number, since it is smaller than the sum of its proper divisors (210205666944).

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

66739510656 is a wasteful number, since it uses less digits than its factorization.

66739510656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158 (or 134 counting only the distinct ones).

The product of its (nonzero) digits is 6123600, while the sum is 54.

The spelling of 66739510656 in words is "sixty-six billion, seven hundred thirty-nine million, five hundred ten thousand, six hundred fifty-six".