21324455437 has 2 divisors, whose sum is σ = 21324455438. Its totient is φ = 21324455436.

The previous prime is 21324455431. The next prime is 21324455441. The reversal of 21324455437 is 73455442312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17533467396 + 3790988041 = 132414^2 + 61571^2 .

It is a cyclic number.

It is not a de Polignac number, because 21324455437 - 2¹¹ = 21324453389 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21324455437.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21324455431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10662227718 + 10662227719.

It is an arithmetic number, because the mean of its divisors is an integer number (10662227719).

Almost surely, 2^21324455437 is an apocalyptic number.

It is an amenable number.

21324455437 is a deficient number, since it is larger than the sum of its proper divisors (1).

21324455437 is an equidigital number, since it uses as much as digits as its factorization.

21324455437 is an evil number, because the sum of its binary digits is even.

The product of its digits is 403200, while the sum is 40.

Adding to 21324455437 its reverse (73455442312), we get a palindrome (94779897749).

The spelling of 21324455437 in words is "twenty-one billion, three hundred twenty-four million, four hundred fifty-five thousand, four hundred thirty-seven".