66138156 has 72 divisors (see below), whose sum is σ = 199390464. Its totient is φ = 18073440.

The previous prime is 66138139. The next prime is 66138157. The reversal of 66138156 is 65183166.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 66138156.

It is not an unprimeable number, because it can be changed into a prime (66138157) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 91 + ... + 11501.

It is an arithmetic number, because the mean of its divisors is an integer number (2769312).

Almost surely, 2^66138156 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66138156, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99695232).

66138156 is an abundant number, since it is smaller than the sum of its proper divisors (133252308).

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

66138156 is a wasteful number, since it uses less digits than its factorization.

66138156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11451 (or 11446 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 66138156 is about 8132.5368735715. The cubic root of 66138156 is about 404.4057861206.

The spelling of 66138156 in words is "sixty-six million, one hundred thirty-eight thousand, one hundred fifty-six".