660721651404 has 24 divisors (see below), whose sum is σ = 1545363301440. Its totient is φ = 219714915024.

The previous prime is 660721651361. The next prime is 660721651411. The reversal of 660721651404 is 404156127066.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65699194 + ... + 65709249.

It is an arithmetic number, because the mean of its divisors is an integer number (64390137560).

Almost surely, 2^660721651404 is an apocalyptic number.

It is an amenable number.

660721651404 is an abundant number, since it is smaller than the sum of its proper divisors (884641650036).

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

660721651404 is a wasteful number, since it uses less digits than its factorization.

660721651404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131408869 (or 131408867 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 42.

The spelling of 660721651404 in words is "six hundred sixty billion, seven hundred twenty-one million, six hundred fifty-one thousand, four hundred four".