43137821 has 2 divisors, whose sum is σ = 43137822. Its totient is φ = 43137820.

The previous prime is 43137793. The next prime is 43137841. The reversal of 43137821 is 12873134.

43137821 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., 41344900 + 1792921 = 6430^2 + 1339^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-43137821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43137841) 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, 21568910 + 21568911.

It is an arithmetic number, because the mean of its divisors is an integer number (21568911).

Almost surely, 2^43137821 is an apocalyptic number.

It is an amenable number.

43137821 is a deficient number, since it is larger than the sum of its proper divisors (1).

43137821 is an equidigital number, since it uses as much as digits as its factorization.

43137821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 29.

The square root of 43137821 is about 6567.9388699957. The cubic root of 43137821 is about 350.7137028466.

The spelling of 43137821 in words is "forty-three million, one hundred thirty-seven thousand, eight hundred twenty-one".