660721798 has 16 divisors (see below), whose sum is σ = 1085011776. Its totient is φ = 299264040.

The previous prime is 660721777. The next prime is 660721807. The reversal of 660721798 is 897127066.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46836 + ... + 59287.

It is an arithmetic number, because the mean of its divisors is an integer number (67813236).

Almost surely, 2^660721798 is an apocalyptic number.

660721798 is a deficient number, since it is larger than the sum of its proper divisors (424289978).

660721798 is a wasteful number, since it uses less digits than its factorization.

660721798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106419.

The product of its (nonzero) digits is 254016, while the sum is 46.

The square root of 660721798 is about 25704.5092931182. The cubic root of 660721798 is about 870.9760473007.

The spelling of 660721798 in words is "six hundred sixty million, seven hundred twenty-one thousand, seven hundred ninety-eight".