661331600 has 30 divisors (see below), whose sum is σ = 1588850130. Its totient is φ = 264532480.

The previous prime is 661331597. The next prime is 661331621. The reversal of 661331600 is 6133166.

661331600 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 3 ways, for example, as 430336 + 660901264 = 656^2 + 25708^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 661331600.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 826265 + ... + 827064.

It is an arithmetic number, because the mean of its divisors is an integer number (52961671).

Almost surely, 2^661331600 is an apocalyptic number.

It is an amenable number.

661331600 is an abundant number, since it is smaller than the sum of its proper divisors (927518530).

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

661331600 is a wasteful number, since it uses less digits than its factorization.

661331600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1653347 (or 1653336 counting only the distinct ones).

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

The square root of 661331600 is about 25716.3683283624. The cubic root of 661331600 is about 871.2439157763.

Adding to 661331600 its reverse (6133166), we get a palindrome (667464766).

The spelling of 661331600 in words is "six hundred sixty-one million, three hundred thirty-one thousand, six hundred".