21104133857 has 2 divisors, whose sum is σ = 21104133858. Its totient is φ = 21104133856.

The previous prime is 21104133769. The next prime is 21104133907. The reversal of 21104133857 is 75833140112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19024409041 + 2079724816 = 137929^2 + 45604^2 .

It is a cyclic number.

It is not a de Polignac number, because 21104133857 - 2¹⁸ = 21103871713 is a prime.

It is not a weakly prime, because it can be changed into another prime (21104123857) 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, 10552066928 + 10552066929.

It is an arithmetic number, because the mean of its divisors is an integer number (10552066929).

Almost surely, 2^21104133857 is an apocalyptic number.

It is an amenable number.

21104133857 is a deficient number, since it is larger than the sum of its proper divisors (1).

21104133857 is an equidigital number, since it uses as much as digits as its factorization.

21104133857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20160, while the sum is 35.

Adding to 21104133857 its reverse (75833140112), we get a palindrome (96937273969).

The spelling of 21104133857 in words is "twenty-one billion, one hundred four million, one hundred thirty-three thousand, eight hundred fifty-seven".