661133600 has 72 divisors (see below), whose sum is σ = 1651613040. Its totient is φ = 258289920.

The previous prime is 661133591. The next prime is 661133609. The reversal of 661133600 is 6331166.

It is an interprime number because it is at equal distance from previous prime (661133591) and next prime (661133609).

It is a self number, because there is not a number n which added to its sum of digits gives 661133600.

It is not an unprimeable number, because it can be changed into a prime (661133609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24791 + ... + 44009.

It is an arithmetic number, because the mean of its divisors is an integer number (22939070).

Almost surely, 2^661133600 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 661133600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (825806520).

661133600 is an abundant number, since it is smaller than the sum of its proper divisors (990479440).

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

661133600 is a wasteful number, since it uses less digits than its factorization.

661133600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19282 (or 19269 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 26.

The square root of 661133600 is about 25712.5183519623. The cubic root of 661133600 is about 871.1569581320.

Adding to 661133600 its reverse (6331166), we get a palindrome (667464766).

The spelling of 661133600 in words is "six hundred sixty-one million, one hundred thirty-three thousand, six hundred".