43581721 has 2 divisors, whose sum is σ = 43581722. Its totient is φ = 43581720.

The previous prime is 43581697. The next prime is 43581731. The reversal of 43581721 is 12718534.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32947600 + 10634121 = 5740^2 + 3261^2 .

It is a cyclic number.

It is not a de Polignac number, because 43581721 - 2⁵ = 43581689 is a prime.

It is not a weakly prime, because it can be changed into another prime (43581731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21790860 + 21790861.

It is an arithmetic number, because the mean of its divisors is an integer number (21790861).

Almost surely, 2^43581721 is an apocalyptic number.

It is an amenable number.

43581721 is a deficient number, since it is larger than the sum of its proper divisors (1).

43581721 is an equidigital number, since it uses as much as digits as its factorization.

43581721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720, while the sum is 31.

The square root of 43581721 is about 6601.6453252201. The cubic root of 43581721 is about 351.9125799825.

The spelling of 43581721 in words is "forty-three million, five hundred eighty-one thousand, seven hundred twenty-one".