66139913 has 8 divisors (see below), whose sum is σ = 75663360. Its totient is φ = 56635200.

The previous prime is 66139907. The next prime is 66139937. The reversal of 66139913 is 31993166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66139913 - 2⁴ = 66139897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66139993) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3953 + ... + 12161.

It is an arithmetic number, because the mean of its divisors is an integer number (9457920).

Almost surely, 2^66139913 is an apocalyptic number.

It is an amenable number.

66139913 is a deficient number, since it is larger than the sum of its proper divisors (9523447).

66139913 is a wasteful number, since it uses less digits than its factorization.

66139913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9367.

The product of its digits is 26244, while the sum is 38.

The square root of 66139913 is about 8132.6448957273. The cubic root of 66139913 is about 404.4093671834.

The spelling of 66139913 in words is "sixty-six million, one hundred thirty-nine thousand, nine hundred thirteen".