66506566 has 16 divisors (see below), whose sum is σ = 114117120. Its totient is φ = 28476360.

The previous prime is 66506549. The next prime is 66506603. The reversal of 66506566 is 66560566.

It is a happy number.

It is a super-2 number, since 2×66506566² = 8846246642224712, which contains 22 as substring.

It is a congruent number.

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, 24925 + ... + 27463.

It is an arithmetic number, because the mean of its divisors is an integer number (7132320).

Almost surely, 2^66506566 is an apocalyptic number.

66506566 is a deficient number, since it is larger than the sum of its proper divisors (47610554).

66506566 is a wasteful number, since it uses less digits than its factorization.

66506566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4419.

The product of its (nonzero) digits is 194400, while the sum is 40.

The square root of 66506566 is about 8155.1557925033. The cubic root of 66506566 is about 405.1552846590.

The spelling of 66506566 in words is "sixty-six million, five hundred six thousand, five hundred sixty-six".