40043213521 has 2 divisors, whose sum is σ = 40043213522. Its totient is φ = 40043213520.

The previous prime is 40043213519. The next prime is 40043213527. The reversal of 40043213521 is 12531234004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23975115921 + 16068097600 = 154839^2 + 126760^2 .

It is a cyclic number.

It is not a de Polignac number, because 40043213521 - 2¹ = 40043213519 is a prime.

Together with 40043213519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (40043213527) 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, 20021606760 + 20021606761.

It is an arithmetic number, because the mean of its divisors is an integer number (20021606761).

Almost surely, 2^40043213521 is an apocalyptic number.

It is an amenable number.

40043213521 is a deficient number, since it is larger than the sum of its proper divisors (1).

40043213521 is an equidigital number, since it uses as much as digits as its factorization.

40043213521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 25.

Adding to 40043213521 its reverse (12531234004), we get a palindrome (52574447525).

The spelling of 40043213521 in words is "forty billion, forty-three million, two hundred thirteen thousand, five hundred twenty-one".