43531681 has 4 divisors (see below), whose sum is σ = 43752852. Its totient is φ = 43310512.

The previous prime is 43531673. The next prime is 43531687. The reversal of 43531681 is 18613534.

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 29160000 + 14371681 = 5400^2 + 3791^2 .

It is a cyclic number.

It is not a de Polignac number, because 43531681 - 2³ = 43531673 is a prime.

It is a super-2 number, since 2×43531681² = 3790014501371522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (43531687) 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, 110290 + ... + 110683.

It is an arithmetic number, because the mean of its divisors is an integer number (10938213).

Almost surely, 2^43531681 is an apocalyptic number.

It is an amenable number.

43531681 is a deficient number, since it is larger than the sum of its proper divisors (221171).

43531681 is a wasteful number, since it uses less digits than its factorization.

43531681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221170.

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

The square root of 43531681 is about 6597.8542724131. The cubic root of 43531681 is about 351.7778411581. Note that the first 3 decimals are identical.

The spelling of 43531681 in words is "forty-three million, five hundred thirty-one thousand, six hundred eighty-one".