661968288 has 120 divisors (see below), whose sum is σ = 1994634180. Its totient is φ = 215239680.

The previous prime is 661968277. The next prime is 661968289. The reversal of 661968288 is 882869166.

It is a happy number.

661968288 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 611671824 + 50296464 = 24732^2 + 7092^2 .

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

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (661968289) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 103158 + ... + 109386.

Almost surely, 2^661968288 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 661968288, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (997317090).

661968288 is an abundant number, since it is smaller than the sum of its proper divisors (1332665892).

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

661968288 is a wasteful number, since it uses less digits than its factorization.

661968288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6292 (or 6275 counting only the distinct ones).

The product of its digits is 1990656, while the sum is 54.

The square root of 661968288 is about 25728.7443922163. The cubic root of 661968288 is about 871.5234188415.

The spelling of 661968288 in words is "six hundred sixty-one million, nine hundred sixty-eight thousand, two hundred eighty-eight".