43684508821 has 2 divisors, whose sum is σ = 43684508822. Its totient is φ = 43684508820.

The previous prime is 43684508809. The next prime is 43684508843. The reversal of 43684508821 is 12880548634.

43684508821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40981548721 + 2702960100 = 202439^2 + 51990^2 .

It is a cyclic number.

It is not a de Polignac number, because 43684508821 - 2¹⁷ = 43684377749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43684508851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21842254410 + 21842254411.

It is an arithmetic number, because the mean of its divisors is an integer number (21842254411).

Almost surely, 2^43684508821 is an apocalyptic number.

It is an amenable number.

43684508821 is a deficient number, since it is larger than the sum of its proper divisors (1).

43684508821 is an equidigital number, since it uses as much as digits as its factorization.

43684508821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1474560, while the sum is 49.

The spelling of 43684508821 in words is "forty-three billion, six hundred eighty-four million, five hundred eight thousand, eight hundred twenty-one".