66661565610 has 16 divisors (see below), whose sum is σ = 159987757536. Its totient is φ = 17776417488.

The previous prime is 66661565561. The next prime is 66661565671. The reversal of 66661565610 is 1656516666.

66661565610 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 66661565610.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1111026064 + ... + 1111026123.

It is an arithmetic number, because the mean of its divisors is an integer number (9999234846).

Almost surely, 2^66661565610 is an apocalyptic number.

66661565610 is an abundant number, since it is smaller than the sum of its proper divisors (93326191926).

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

66661565610 is a wasteful number, since it uses less digits than its factorization.

66661565610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2222052197.

The product of its (nonzero) digits is 1166400, while the sum is 48.

It can be divided in two parts, 6666156 and 5610, that added together give a palindrome (6671766).

The spelling of 66661565610 in words is "sixty-six billion, six hundred sixty-one million, five hundred sixty-five thousand, six hundred ten".