66660511566 has 32 divisors (see below), whose sum is σ = 145651694976. Its totient is φ = 20170908000.

The previous prime is 66660511543. The next prime is 66660511583. The reversal of 66660511566 is 66511506666.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 685225 + ... + 776436.

It is an arithmetic number, because the mean of its divisors is an integer number (4551615468).

Almost surely, 2^66660511566 is an apocalyptic number.

66660511566 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

66660511566 is an abundant number, since it is smaller than the sum of its proper divisors (78991183410).

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

66660511566 is a wasteful number, since it uses less digits than its factorization.

66660511566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1462368.

The product of its (nonzero) digits is 1166400, while the sum is 48.

The spelling of 66660511566 in words is "sixty-six billion, six hundred sixty million, five hundred eleven thousand, five hundred sixty-six".