66805921312 has 48 divisors (see below), whose sum is σ = 142592146200. Its totient is φ = 30626537472.

The previous prime is 66805921291. The next prime is 66805921327. The reversal of 66805921312 is 21312950866.

It can be written as a sum of positive squares in 4 ways, for example, as 50174208016 + 16631713296 = 223996^2 + 128964^2 .

It is a super-2 number, since 2×66805921312² (a number of 22 digits) contains 22 as substring.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 476913 + ... + 600880.

Almost surely, 2^66805921312 is an apocalyptic number.

It is an amenable number.

66805921312 is an abundant number, since it is smaller than the sum of its proper divisors (75786224888).

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

66805921312 is a wasteful number, since it uses less digits than its factorization.

66805921312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1077965 (or 1077957 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 43.

The spelling of 66805921312 in words is "sixty-six billion, eight hundred five million, nine hundred twenty-one thousand, three hundred twelve".