661116669660 has 384 divisors, whose sum is σ = 2165058201600. Its totient is φ = 167246069760.

The previous prime is 661116669641. The next prime is 661116669677. The reversal of 661116669660 is 66966611166.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 661116669597 and 661116669606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 672549529 + ... + 672550511.

It is an arithmetic number, because the mean of its divisors is an integer number (5638172400).

Almost surely, 2^661116669660 is an apocalyptic number.

661116669660 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661116669660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1082529100800).

661116669660 is an abundant number, since it is smaller than the sum of its proper divisors (1503941531940).

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

661116669660 is a wasteful number, since it uses less digits than its factorization.

661116669660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1738 (or 1730 counting only the distinct ones).

The product of its (nonzero) digits is 2519424, while the sum is 54.

The spelling of 661116669660 in words is "six hundred sixty-one billion, one hundred sixteen million, six hundred sixty-nine thousand, six hundred sixty".