666610688419128 has 128 divisors (see below), whose sum is σ = 1883313154080000. Its totient is φ = 218410475584896.

The previous prime is 666610688419127. The next prime is 666610688419147. The reversal of 666610688419128 is 821914886016666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666610688419127) 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, 100299778 + ... + 106739246.

It is an arithmetic number, because the mean of its divisors is an integer number (14713384016250).

Almost surely, 2^{666610688419128} 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 666610688419128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (941656577040000).

666610688419128 is an abundant number, since it is smaller than the sum of its proper divisors (1216702465660872).

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

666610688419128 is a wasteful number, since it uses less digits than its factorization.

666610688419128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6447666 (or 6447656 counting only the distinct ones).

The product of its (nonzero) digits is 286654464, while the sum is 72.

The spelling of 666610688419128 in words is "six hundred sixty-six trillion, six hundred ten billion, six hundred eighty-eight million, four hundred nineteen thousand, one hundred twenty-eight".