43940821 has 2 divisors, whose sum is σ = 43940822. Its totient is φ = 43940820.

The previous prime is 43940803. The next prime is 43940839. The reversal of 43940821 is 12804934.

It is a balanced prime because it is at equal distance from previous prime (43940803) and next prime (43940839).

It can be written as a sum of positive squares in only one way, i.e., 41088100 + 2852721 = 6410^2 + 1689^2 .

It is a cyclic number.

It is not a de Polignac number, because 43940821 - 2²³ = 35552213 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43940851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21970410 + 21970411.

It is an arithmetic number, because the mean of its divisors is an integer number (21970411).

Almost surely, 2^43940821 is an apocalyptic number.

It is an amenable number.

43940821 is a deficient number, since it is larger than the sum of its proper divisors (1).

43940821 is an equidigital number, since it uses as much as digits as its factorization.

43940821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 43940821 is about 6628.7872948225. The cubic root of 43940821 is about 352.8764879118.

The spelling of 43940821 in words is "forty-three million, nine hundred forty thousand, eight hundred twenty-one".