66801408138 has 12 divisors (see below), whose sum is σ = 144736384338. Its totient is φ = 22267136040.

The previous prime is 66801408119. The next prime is 66801408143. The reversal of 66801408138 is 83180410866.

It is a happy number.

66801408138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 41397192369 + 25404215769 = 203463^2 + 159387^2 .

It is a junction number, because it is equal to n+sod(n) for n = 66801408093 and 66801408102.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1855594653 + ... + 1855594688.

Almost surely, 2^66801408138 is an apocalyptic number.

66801408138 is an abundant number, since it is smaller than the sum of its proper divisors (77934976200).

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

66801408138 is a wasteful number, since it uses less digits than its factorization.

66801408138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3711189349 (or 3711189346 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 45.

The spelling of 66801408138 in words is "sixty-six billion, eight hundred one million, four hundred eight thousand, one hundred thirty-eight".