66581904 has 20 divisors (see below), whose sum is σ = 172003376. Its totient is φ = 22193952.

The previous prime is 66581903. The next prime is 66581917. The reversal of 66581904 is 40918566.

It is not an unprimeable number, because it can be changed into a prime (66581903) 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, 693514 + ... + 693609.

Almost surely, 2^66581904 is an apocalyptic number.

It is an amenable number.

66581904 is an abundant number, since it is smaller than the sum of its proper divisors (105421472).

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

66581904 is a wasteful number, since it uses less digits than its factorization.

66581904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1387134 (or 1387128 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 39.

The square root of 66581904 is about 8159.7735262690. The cubic root of 66581904 is about 405.3082122685.

The spelling of 66581904 in words is "sixty-six million, five hundred eighty-one thousand, nine hundred four".