43138561 has 4 divisors (see below), whose sum is σ = 43162624. Its totient is φ = 43114500.

The previous prime is 43138549. The next prime is 43138619. The reversal of 43138561 is 16583134.

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 43138561 - 2²⁵ = 9584129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (43138861) 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, 9105 + ... + 13006.

It is an arithmetic number, because the mean of its divisors is an integer number (10790656).

Almost surely, 2^43138561 is an apocalyptic number.

It is an amenable number.

43138561 is a deficient number, since it is larger than the sum of its proper divisors (24063).

43138561 is a wasteful number, since it uses less digits than its factorization.

43138561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24062.

The product of its digits is 8640, while the sum is 31.

The square root of 43138561 is about 6567.9952040177. The cubic root of 43138561 is about 350.7157082535.

The spelling of 43138561 in words is "forty-three million, one hundred thirty-eight thousand, five hundred sixty-one".