43821681 has 16 divisors (see below), whose sum is σ = 59496000. Its totient is φ = 28684800.

The previous prime is 43821671. The next prime is 43821689. The reversal of 43821681 is 18612834.

43821681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 43821681 - 2¹³ = 43813489 is a prime.

It is a super-2 number, since 2×43821681² = 3840679451331522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (43821689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87570 + ... + 88068.

It is an arithmetic number, because the mean of its divisors is an integer number (3718500).

Almost surely, 2^43821681 is an apocalyptic number.

It is an amenable number.

43821681 is a deficient number, since it is larger than the sum of its proper divisors (15674319).

43821681 is a wasteful number, since it uses less digits than its factorization.

43821681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 976.

The product of its digits is 9216, while the sum is 33.

The square root of 43821681 is about 6619.7946342768. The cubic root of 43821681 is about 352.5572725210.

The spelling of 43821681 in words is "forty-three million, eight hundred twenty-one thousand, six hundred eighty-one".