21232421237 has 2 divisors, whose sum is σ = 21232421238. Its totient is φ = 21232421236.

The previous prime is 21232421123. The next prime is 21232421267. The reversal of 21232421237 is 73212423212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15966596881 + 5265824356 = 126359^2 + 72566^2 .

It is a cyclic number.

It is not a de Polignac number, because 21232421237 - 2⁸ = 21232420981 is a prime.

It is a super-2 number, since 2×21232421237² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21232421267) 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, 10616210618 + 10616210619.

It is an arithmetic number, because the mean of its divisors is an integer number (10616210619).

Almost surely, 2^21232421237 is an apocalyptic number.

It is an amenable number.

21232421237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21232421237 is an equidigital number, since it uses as much as digits as its factorization.

21232421237 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 29.

Adding to 21232421237 its reverse (73212423212), we get a palindrome (94444844449).

The spelling of 21232421237 in words is "twenty-one billion, two hundred thirty-two million, four hundred twenty-one thousand, two hundred thirty-seven".