66610656 has 288 divisors, whose sum is σ = 239016960. Its totient is φ = 17169408.

The previous prime is 66610639. The next prime is 66610657. The reversal of 66610656 is 65601666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 66610656.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66610657) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1417225 + ... + 1417271.

It is an arithmetic number, because the mean of its divisors is an integer number (829920).

Almost surely, 2^66610656 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 66610656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119508480).

66610656 is an abundant number, since it is smaller than the sum of its proper divisors (172406304).

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

66610656 is a wasteful number, since it uses less digits than its factorization.

66610656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 66610656 is about 8161.5351497130. The cubic root of 66610656 is about 405.3665451588.

It can be divided in two parts, 666 and 10656, that multiplied together give a square (7096896 = 2664²).

The spelling of 66610656 in words is "sixty-six million, six hundred ten thousand, six hundred fifty-six".