66581890 has 16 divisors (see below), whose sum is σ = 126155520. Its totient is φ = 25230960.

The previous prime is 66581881. The next prime is 66581903. The reversal of 66581890 is 9818566.

It is an unprimeable number.

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, 175026 + ... + 175405.

It is an arithmetic number, because the mean of its divisors is an integer number (7884720).

Almost surely, 2^66581890 is an apocalyptic number.

66581890 is a deficient number, since it is larger than the sum of its proper divisors (59573630).

66581890 is a wasteful number, since it uses less digits than its factorization.

66581890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350457.

The product of its (nonzero) digits is 103680, while the sum is 43.

The square root of 66581890 is about 8159.7726684020. The cubic root of 66581890 is about 405.3081838608.

The spelling of 66581890 in words is "sixty-six million, five hundred eighty-one thousand, eight hundred ninety".