661807788 has 48 divisors (see below), whose sum is σ = 1575836640. Its totient is φ = 216115200.

The previous prime is 661807771. The next prime is 661807823. The reversal of 661807788 is 887708166.

661807788 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 661807788.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 195228 + ... + 198588.

It is an arithmetic number, because the mean of its divisors is an integer number (32829930).

Almost surely, 2^661807788 is an apocalyptic number.

It is an amenable number.

661807788 is an abundant number, since it is smaller than the sum of its proper divisors (914028852).

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

661807788 is a wasteful number, since it uses less digits than its factorization.

661807788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3698 (or 3696 counting only the distinct ones).

The product of its (nonzero) digits is 903168, while the sum is 51.

The square root of 661807788 is about 25725.6251236000. The cubic root of 661807788 is about 871.4529769902.

The spelling of 661807788 in words is "six hundred sixty-one million, eight hundred seven thousand, seven hundred eighty-eight".