21254872321 has 2 divisors, whose sum is σ = 21254872322. Its totient is φ = 21254872320.

The previous prime is 21254872313. The next prime is 21254872339. The reversal of 21254872321 is 12327845212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15518930625 + 5735941696 = 124575^2 + 75736^2 .

It is a cyclic number.

It is not a de Polignac number, because 21254872321 - 2³ = 21254872313 is a prime.

It is not a weakly prime, because it can be changed into another prime (21254872621) 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, 10627436160 + 10627436161.

It is an arithmetic number, because the mean of its divisors is an integer number (10627436161).

Almost surely, 2^21254872321 is an apocalyptic number.

It is an amenable number.

21254872321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21254872321 is an equidigital number, since it uses as much as digits as its factorization.

21254872321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 53760, while the sum is 37.

The spelling of 21254872321 in words is "twenty-one billion, two hundred fifty-four million, eight hundred seventy-two thousand, three hundred twenty-one".