66138413 has 4 divisors (see below), whose sum is σ = 72151008. Its totient is φ = 60125820.

The previous prime is 66138367. The next prime is 66138427. The reversal of 66138413 is 31483166.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66138413 - 2⁸ = 66138157 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66138413.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66138713) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3006281 + ... + 3006302.

It is an arithmetic number, because the mean of its divisors is an integer number (18037752).

Almost surely, 2^66138413 is an apocalyptic number.

It is an amenable number.

66138413 is a deficient number, since it is larger than the sum of its proper divisors (6012595).

66138413 is a wasteful number, since it uses less digits than its factorization.

66138413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6012594.

The product of its digits is 10368, while the sum is 32.

The square root of 66138413 is about 8132.5526742838. The cubic root of 66138413 is about 404.4063099340.

The spelling of 66138413 in words is "sixty-six million, one hundred thirty-eight thousand, four hundred thirteen".