66640246660 has 96 divisors (see below), whose sum is σ = 158463295200. Its totient is φ = 23367536640.

The previous prime is 66640246637. The next prime is 66640246661. The reversal of 66640246660 is 6664204666.

It can be written as a sum of positive squares in 16 ways, for example, as 37201922884 + 29438323776 = 192878^2 + 171576^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 66640246660.

It is not an unprimeable number, because it can be changed into a prime (66640246661) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 387496 + ... + 532384.

It is an arithmetic number, because the mean of its divisors is an integer number (1650659325).

Almost surely, 2^66640246660 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 66640246660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (79231647600).

66640246660 is an abundant number, since it is smaller than the sum of its proper divisors (91823048540).

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

66640246660 is a wasteful number, since it uses less digits than its factorization.

66640246660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145001 (or 144999 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 46.

The spelling of 66640246660 in words is "sixty-six billion, six hundred forty million, two hundred forty-six thousand, six hundred sixty".