664799481 has 20 divisors (see below), whose sum is σ = 994539172. Its totient is φ = 442555488.

The previous prime is 664799477. The next prime is 664799519. The reversal of 664799481 is 184997466.

664799481 is a `hidden beast` number, since 6 + 6 + 479 + 94 + 81 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 446941881 + 217857600 = 21141^2 + 14760^2 .

It is not a de Polignac number, because 664799481 - 2² = 664799477 is a prime.

It is a super-2 number, since 2×664799481² = 883916699875738722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664799081) by changing a digit.

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 19 ways as a sum of consecutive naturals, for example, 53775 + ... + 64971.

Almost surely, 2^664799481 is an apocalyptic number.

It is an amenable number.

664799481 is a deficient number, since it is larger than the sum of its proper divisors (329739691).

664799481 is a wasteful number, since it uses less digits than its factorization.

664799481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11942 (or 11933 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 54.

The square root of 664799481 is about 25783.7057266794. The cubic root of 664799481 is about 872.7641336793.

The spelling of 664799481 in words is "six hundred sixty-four million, seven hundred ninety-nine thousand, four hundred eighty-one".