43309561 has 3 divisors (see below), whose sum is σ = 43316143. Its totient is φ = 43302980.

The previous prime is 43309547. The next prime is 43309577. The reversal of 43309561 is 16590334.

The square root of 43309561 is 6581.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 10361961 + 32947600 = 3219^2 + 5740^2 .

It is not a de Polignac number, because 43309561 - 2¹¹ = 43307513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (43309501) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 3291 + ... + 9871.

Almost surely, 2^43309561 is an apocalyptic number.

43309561 is the 6581-st square number.

43309561 is the 3291-st centered octagonal number.

It is an amenable number.

43309561 is a deficient number, since it is larger than the sum of its proper divisors (6582).

43309561 is an frugal number, since it uses more digits than its factorization.

43309561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13162 (or 6581 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 31.

The cubic root of 43309561 is about 351.1785062378.

Adding to 43309561 its reverse (16590334), we get a palindrome (59899895).

The spelling of 43309561 in words is "forty-three million, three hundred nine thousand, five hundred sixty-one".