66138140 has 12 divisors (see below), whose sum is σ = 138890136. Its totient is φ = 26455248.

The previous prime is 66138139. The next prime is 66138157. The reversal of 66138140 is 4183166.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1653434 + ... + 1653473.

It is an arithmetic number, because the mean of its divisors is an integer number (11574178).

Almost surely, 2^66138140 is an apocalyptic number.

It is an amenable number.

66138140 is an abundant number, since it is smaller than the sum of its proper divisors (72751996).

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

66138140 is a wasteful number, since it uses less digits than its factorization.

66138140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3306916 (or 3306914 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 66138140 is about 8132.5358898685. The cubic root of 66138140 is about 404.4057535096.

The spelling of 66138140 in words is "sixty-six million, one hundred thirty-eight thousand, one hundred forty".