43431313021 has 2 divisors, whose sum is σ = 43431313022. Its totient is φ = 43431313020.

The previous prime is 43431312979. The next prime is 43431313031. The reversal of 43431313021 is 12031313434.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42482980996 + 948332025 = 206114^2 + 30795^2 .

It is a cyclic number.

It is not a de Polignac number, because 43431313021 - 2³¹ = 41283829373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43431313031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21715656510 + 21715656511.

It is an arithmetic number, because the mean of its divisors is an integer number (21715656511).

Almost surely, 2^43431313021 is an apocalyptic number.

It is an amenable number.

43431313021 is a deficient number, since it is larger than the sum of its proper divisors (1).

43431313021 is an equidigital number, since it uses as much as digits as its factorization.

43431313021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 25.

Adding to 43431313021 its reverse (12031313434), we get a palindrome (55462626455).

The spelling of 43431313021 in words is "forty-three billion, four hundred thirty-one million, three hundred thirteen thousand, twenty-one".