21323120257 has 2 divisors, whose sum is σ = 21323120258. Its totient is φ = 21323120256.

The previous prime is 21323120237. The next prime is 21323120297. The reversal of 21323120257 is 75202132312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20497362561 + 825757696 = 143169^2 + 28736^2 .

It is a cyclic number.

It is not a de Polignac number, because 21323120257 - 2³¹ = 19175636609 is a prime.

It is not a weakly prime, because it can be changed into another prime (21323120237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10661560128 + 10661560129.

It is an arithmetic number, because the mean of its divisors is an integer number (10661560129).

Almost surely, 2^21323120257 is an apocalyptic number.

It is an amenable number.

21323120257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21323120257 is an equidigital number, since it uses as much as digits as its factorization.

21323120257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 28.

Adding to 21323120257 its reverse (75202132312), we get a palindrome (96525252569).

The spelling of 21323120257 in words is "twenty-one billion, three hundred twenty-three million, one hundred twenty thousand, two hundred fifty-seven".