43138813 has 4 divisors (see below), whose sum is σ = 43160320. Its totient is φ = 43117308.

The previous prime is 43138787. The next prime is 43138831. The reversal of 43138813 is 31883134.

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, and also an emirpimes, since its reverse is a distinct semiprime: 31883134 = 2 ⋅15941567.

It is a cyclic number.

It is not a de Polignac number, because 43138813 - 2⁹ = 43138301 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43138213) 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, 7395 + ... + 11872.

It is an arithmetic number, because the mean of its divisors is an integer number (10790080).

Almost surely, 2^43138813 is an apocalyptic number.

It is an amenable number.

43138813 is a deficient number, since it is larger than the sum of its proper divisors (21507).

43138813 is a wasteful number, since it uses less digits than its factorization.

43138813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21506.

The product of its digits is 6912, while the sum is 31.

The square root of 43138813 is about 6568.0143879258. The cubic root of 43138813 is about 350.7163911706.

The spelling of 43138813 in words is "forty-three million, one hundred thirty-eight thousand, eight hundred thirteen".