21303120231257 has 2 divisors, whose sum is σ = 21303120231258. Its totient is φ = 21303120231256.

The previous prime is 21303120231137. The next prime is 21303120231293. The reversal of 21303120231257 is 75213202130312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17361422223616 + 3941698007641 = 4166704^2 + 1985371^2 .

It is a cyclic number.

It is not a de Polignac number, because 21303120231257 - 2¹² = 21303120227161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21303120233257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10651560115628 + 10651560115629.

It is an arithmetic number, because the mean of its divisors is an integer number (10651560115629).

Almost surely, 2^{21303120231257} is an apocalyptic number.

It is an amenable number.

21303120231257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21303120231257 is an equidigital number, since it uses as much as digits as its factorization.

21303120231257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15120, while the sum is 32.

Adding to 21303120231257 its reverse (75213202130312), we get a palindrome (96516322361569).

The spelling of 21303120231257 in words is "twenty-one trillion, three hundred three billion, one hundred twenty million, two hundred thirty-one thousand, two hundred fifty-seven".