21023321237 has 2 divisors, whose sum is σ = 21023321238. Its totient is φ = 21023321236.

The previous prime is 21023321203. The next prime is 21023321273. The reversal of 21023321237 is 73212332012.

It is a happy number.

Together with next prime (21023321273) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16587894436 + 4435426801 = 128794^2 + 66599^2 .

It is a cyclic number.

It is not a de Polignac number, because 21023321237 - 2³⁰ = 19949579413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21023321537) 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, 10511660618 + 10511660619.

It is an arithmetic number, because the mean of its divisors is an integer number (10511660619).

Almost surely, 2^21023321237 is an apocalyptic number.

It is an amenable number.

21023321237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21023321237 is an equidigital number, since it uses as much as digits as its factorization.

21023321237 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 26.

Adding to 21023321237 its reverse (73212332012), we get a palindrome (94235653249).

The spelling of 21023321237 in words is "twenty-one billion, twenty-three million, three hundred twenty-one thousand, two hundred thirty-seven".