66756620 has 72 divisors (see below), whose sum is σ = 172712736. Its totient is φ = 21536256.

The previous prime is 66756583. The next prime is 66756623. The reversal of 66756620 is 2665766.

It is not an unprimeable number, because it can be changed into a prime (66756623) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14657 + ... + 18663.

It is an arithmetic number, because the mean of its divisors is an integer number (2398788).

Almost surely, 2^66756620 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 66756620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86356368).

66756620 is an abundant number, since it is smaller than the sum of its proper divisors (105956116).

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

66756620 is a wasteful number, since it uses less digits than its factorization.

66756620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4047 (or 4038 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 38.

The square root of 66756620 is about 8170.4724465602. The cubic root of 66756620 is about 405.6624225229.

It can be divided in two parts, 66756 and 620, that added together give a palindrome (67376).

The spelling of 66756620 in words is "sixty-six million, seven hundred fifty-six thousand, six hundred twenty".