66644404056 has 48 divisors (see below), whose sum is σ = 180533808000. Its totient is φ = 22210057152.

The previous prime is 66644404051. The next prime is 66644404061. The reversal of 66644404056 is 65040444666.

It is an interprime number because it is at equal distance from previous prime (66644404051) and next prime (66644404061).

It is a super-2 number, since 2×66644404056² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66644404051) by changing a digit.

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, 249090 + ... + 441966.

It is an arithmetic number, because the mean of its divisors is an integer number (3761121000).

Almost surely, 2^66644404056 is an apocalyptic number.

It is an amenable number.

66644404056 is an abundant number, since it is smaller than the sum of its proper divisors (113889403944).

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

66644404056 is a wasteful number, since it uses less digits than its factorization.

66644404056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197688 (or 197681 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 45.

The spelling of 66644404056 in words is "sixty-six billion, six hundred forty-four million, four hundred four thousand, fifty-six".