661161960 has 128 divisors (see below), whose sum is σ = 2333577600. Its totient is φ = 165934080.

The previous prime is 661161953. The next prime is 661161961. The reversal of 661161960 is 69161166.

661161960 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (661161961) 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, 355 + ... + 36365.

It is an arithmetic number, because the mean of its divisors is an integer number (18231075).

Almost surely, 2^661161960 is an apocalyptic number.

661161960 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 661161960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1166788800).

661161960 is an abundant number, since it is smaller than the sum of its proper divisors (1672415640).

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

661161960 is a wasteful number, since it uses less digits than its factorization.

661161960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36048 (or 36038 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 661161960 is about 25713.0698283966. The cubic root of 661161960 is about 871.1694143426.

The spelling of 661161960 in words is "six hundred sixty-one million, one hundred sixty-one thousand, nine hundred sixty".