66506605 has 16 divisors (see below), whose sum is σ = 87381504. Its totient is φ = 48191680.

The previous prime is 66506603. The next prime is 66506611. The reversal of 66506605 is 50660566.

It is not a de Polignac number, because 66506605 - 2¹ = 66506603 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66506603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14052 + ... + 18178.

It is an arithmetic number, because the mean of its divisors is an integer number (5461344).

Almost surely, 2^66506605 is an apocalyptic number.

It is an amenable number.

66506605 is a deficient number, since it is larger than the sum of its proper divisors (20874899).

66506605 is a wasteful number, since it uses less digits than its factorization.

66506605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4436.

The product of its (nonzero) digits is 32400, while the sum is 34.

The square root of 66506605 is about 8155.1581836283. The cubic root of 66506605 is about 405.1553638544.

The spelling of 66506605 in words is "sixty-six million, five hundred six thousand, six hundred five".