43631821 has 2 divisors, whose sum is σ = 43631822. Its totient is φ = 43631820.

The previous prime is 43631737. The next prime is 43631827. The reversal of 43631821 is 12813634.

43631821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26409321 + 17222500 = 5139^2 + 4150^2 .

It is a cyclic number.

It is not a de Polignac number, because 43631821 - 2¹⁷ = 43500749 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 43631821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43631827) 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 as a sum of consecutive naturals, namely, 21815910 + 21815911.

It is an arithmetic number, because the mean of its divisors is an integer number (21815911).

Almost surely, 2^43631821 is an apocalyptic number.

It is an amenable number.

43631821 is a deficient number, since it is larger than the sum of its proper divisors (1).

43631821 is an equidigital number, since it uses as much as digits as its factorization.

43631821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 28.

The square root of 43631821 is about 6605.4387439443. The cubic root of 43631821 is about 352.0473770812.

The spelling of 43631821 in words is "forty-three million, six hundred thirty-one thousand, eight hundred twenty-one".