661159177168 has 160 divisors (see below), whose sum is σ = 1611603993600. Its totient is φ = 261652285440.

The previous prime is 661159177141. The next prime is 661159177169. The reversal of 661159177168 is 861771951166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661159177169) 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, 4877833 + ... + 5011543.

It is an arithmetic number, because the mean of its divisors is an integer number (10072524960).

Almost surely, 2^661159177168 is an apocalyptic number.

661159177168 is a gapful number since it is divisible by the number (68) 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 661159177168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (805801996800).

661159177168 is an abundant number, since it is smaller than the sum of its proper divisors (950444816432).

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

661159177168 is a wasteful number, since it uses less digits than its factorization.

661159177168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133810 (or 133790 counting only the distinct ones).

The product of its digits is 3810240, while the sum is 58.

The spelling of 661159177168 in words is "six hundred sixty-one billion, one hundred fifty-nine million, one hundred seventy-seven thousand, one hundred sixty-eight".