66810943256 has 8 divisors (see below), whose sum is σ = 125270518620. Its totient is φ = 33405471624.

The previous prime is 66810943249. The next prime is 66810943259. The reversal of 66810943256 is 65234901866.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66810943259) 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 as a sum of consecutive naturals, namely, 4175683946 + ... + 4175683961.

Almost surely, 2^66810943256 is an apocalyptic number.

It is an amenable number.

66810943256 is a deficient number, since it is larger than the sum of its proper divisors (58459575364).

66810943256 is a wasteful number, since it uses less digits than its factorization.

66810943256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8351367913 (or 8351367909 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 50.

The spelling of 66810943256 in words is "sixty-six billion, eight hundred ten million, nine hundred forty-three thousand, two hundred fifty-six".