660641788 has 12 divisors (see below), whose sum is σ = 1206389520. Its totient is φ = 315959072.

The previous prime is 660641783. The next prime is 660641797. The reversal of 660641788 is 887146066.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660641783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3590353 + ... + 3590536.

It is an arithmetic number, because the mean of its divisors is an integer number (100532460).

Almost surely, 2^660641788 is an apocalyptic number.

It is an amenable number.

660641788 is a deficient number, since it is larger than the sum of its proper divisors (545747732).

660641788 is a wasteful number, since it uses less digits than its factorization.

660641788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7180916 (or 7180914 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 46.

The square root of 660641788 is about 25702.9529042871. The cubic root of 660641788 is about 870.9408889800.

The spelling of 660641788 in words is "six hundred sixty million, six hundred forty-one thousand, seven hundred eighty-eight".