21054438793 has 2 divisors, whose sum is σ = 21054438794. Its totient is φ = 21054438792.

The previous prime is 21054438791. The next prime is 21054438803. The reversal of 21054438793 is 39783445012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11330112249 + 9724326544 = 106443^2 + 98612^2 .

It is a cyclic number.

It is not a de Polignac number, because 21054438793 - 2¹ = 21054438791 is a prime.

Together with 21054438791, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21054438791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10527219396 + 10527219397.

It is an arithmetic number, because the mean of its divisors is an integer number (10527219397).

Almost surely, 2^21054438793 is an apocalyptic number.

It is an amenable number.

21054438793 is a deficient number, since it is larger than the sum of its proper divisors (1).

21054438793 is an equidigital number, since it uses as much as digits as its factorization.

21054438793 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 725760, while the sum is 46.

The spelling of 21054438793 in words is "twenty-one billion, fifty-four million, four hundred thirty-eight thousand, seven hundred ninety-three".