43213661 has 4 divisors (see below), whose sum is σ = 43236672. Its totient is φ = 43190652.

The previous prime is 43213637. The next prime is 43213693. The reversal of 43213661 is 16631234.

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 a de Polignac number, because none of the positive numbers 2^k-43213661 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 43213661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43213061) 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, 8411 + ... + 12536.

It is an arithmetic number, because the mean of its divisors is an integer number (10809168).

Almost surely, 2^43213661 is an apocalyptic number.

It is an amenable number.

43213661 is a deficient number, since it is larger than the sum of its proper divisors (23011).

43213661 is a wasteful number, since it uses less digits than its factorization.

43213661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23010.

The product of its digits is 2592, while the sum is 26.

The square root of 43213661 is about 6573.7098353974. The cubic root of 43213661 is about 350.9191108045.

Adding to 43213661 its reverse (16631234), we get a palindrome (59844895).

The spelling of 43213661 in words is "forty-three million, two hundred thirteen thousand, six hundred sixty-one".