21927234821 has 2 divisors, whose sum is σ = 21927234822. Its totient is φ = 21927234820.

The previous prime is 21927234809. The next prime is 21927234827. The reversal of 21927234821 is 12843272912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15818092900 + 6109141921 = 125770^2 + 78161^2 .

It is a cyclic number.

It is not a de Polignac number, because 21927234821 - 2¹⁸ = 21926972677 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21927234827) 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, 10963617410 + 10963617411.

It is an arithmetic number, because the mean of its divisors is an integer number (10963617411).

Almost surely, 2^21927234821 is an apocalyptic number.

It is an amenable number.

21927234821 is a deficient number, since it is larger than the sum of its proper divisors (1).

21927234821 is an equidigital number, since it uses as much as digits as its factorization.

21927234821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 41.

The spelling of 21927234821 in words is "twenty-one billion, nine hundred twenty-seven million, two hundred thirty-four thousand, eight hundred twenty-one".