66511566 has 24 divisors (see below), whose sum is σ = 157209624. Its totient is φ = 20154960.

The previous prime is 66511547. The next prime is 66511597.

66511566 is nontrivially palindromic in base 10.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 66511566.

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 11 ways as a sum of consecutive naturals, for example, 167761 + ... + 168156.

It is an arithmetic number, because the mean of its divisors is an integer number (6550401).

Almost surely, 2^66511566 is an apocalyptic number.

66511566 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

66511566 is an abundant number, since it is smaller than the sum of its proper divisors (90698058).

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

66511566 is a wasteful number, since it uses less digits than its factorization.

66511566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 335936 (or 335933 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 66511566 is about 8155.4623412778. The cubic root of 66511566 is about 405.1654376698.

The spelling of 66511566 in words is "sixty-six million, five hundred eleven thousand, five hundred sixty-six".