665733721928 has 32 divisors (see below), whose sum is σ = 1378134444960. Its totient is φ = 298960375680.

The previous prime is 665733721927. The next prime is 665733721951. The reversal of 665733721928 is 829127337566.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (665733721927) 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 7 ways as a sum of consecutive naturals, for example, 45565925 + ... + 45580532.

It is an arithmetic number, because the mean of its divisors is an integer number (43066701405).

Almost surely, 2^665733721928 is an apocalyptic number.

It is an amenable number.

665733721928 is an abundant number, since it is smaller than the sum of its proper divisors (712400723032).

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

665733721928 is a wasteful number, since it uses less digits than its factorization.

665733721928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91146557 (or 91146553 counting only the distinct ones).

The product of its digits is 22861440, while the sum is 59.

The spelling of 665733721928 in words is "six hundred sixty-five billion, seven hundred thirty-three million, seven hundred twenty-one thousand, nine hundred twenty-eight".