43381561 has 4 divisors (see below), whose sum is σ = 43467300. Its totient is φ = 43295824.

The previous prime is 43381543. The next prime is 43381577. The reversal of 43381561 is 16518334.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 30913600 + 12467961 = 5560^2 + 3531^2 .

It is a cyclic number.

It is not a de Polignac number, because 43381561 - 2⁵ = 43381529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (43381861) 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, 42106 + ... + 43123.

It is an arithmetic number, because the mean of its divisors is an integer number (10866825).

Almost surely, 2^43381561 is an apocalyptic number.

It is an amenable number.

43381561 is a deficient number, since it is larger than the sum of its proper divisors (85739).

43381561 is an equidigital number, since it uses as much as digits as its factorization.

43381561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85738.

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

The square root of 43381561 is about 6586.4680216334. The cubic root of 43381561 is about 351.3730041207.

Adding to 43381561 its reverse (16518334), we get a palindrome (59899895).

The spelling of 43381561 in words is "forty-three million, three hundred eighty-one thousand, five hundred sixty-one".