66915138 has 32 divisors (see below), whose sum is σ = 137491200. Its totient is φ = 21699216.

The previous prime is 66915137. The next prime is 66915161. The reversal of 66915138 is 83151966.

It is a junction number, because it is equal to n+sod(n) for n = 66915096 and 66915105.

It is not an unprimeable number, because it can be changed into a prime (66915137) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 107793 + ... + 108411.

It is an arithmetic number, because the mean of its divisors is an integer number (4296600).

Almost surely, 2^66915138 is an apocalyptic number.

66915138 is an abundant number, since it is smaller than the sum of its proper divisors (70576062).

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

66915138 is a wasteful number, since it uses less digits than its factorization.

66915138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1086.

The product of its digits is 38880, while the sum is 39.

The square root of 66915138 is about 8180.1673577012. The cubic root of 66915138 is about 405.9832594390.

The spelling of 66915138 in words is "sixty-six million, nine hundred fifteen thousand, one hundred thirty-eight".