66281390256 has 40 divisors (see below), whose sum is σ = 180238870720. Its totient is φ = 20930965056.

The previous prime is 66281390251. The next prime is 66281390267. The reversal of 66281390256 is 65209318266.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is not an unprimeable number, because it can be changed into a prime (66281390251) 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 7 ways as a sum of consecutive naturals, for example, 36337570 + ... + 36339393.

It is an arithmetic number, because the mean of its divisors is an integer number (4505971768).

Almost surely, 2^66281390256 is an apocalyptic number.

It is an amenable number.

66281390256 is an abundant number, since it is smaller than the sum of its proper divisors (113957480464).

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

66281390256 is a wasteful number, since it uses less digits than its factorization.

66281390256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72676993 (or 72676987 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 48.

The spelling of 66281390256 in words is "sixty-six billion, two hundred eighty-one million, three hundred ninety thousand, two hundred fifty-six".