21101320113257 has 2 divisors, whose sum is σ = 21101320113258. Its totient is φ = 21101320113256.

The previous prime is 21101320113241. The next prime is 21101320113277. The reversal of 21101320113257 is 75231102310112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11575924280281 + 9525395832976 = 3402341^2 + 3086324^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101320113257 - 2⁴ = 21101320113241 is a prime.

It is a super-2 number, since 2×21101320113257² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21101320113277) 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, 10550660056628 + 10550660056629.

It is an arithmetic number, because the mean of its divisors is an integer number (10550660056629).

Almost surely, 2^{21101320113257} is an apocalyptic number.

It is an amenable number.

21101320113257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101320113257 is an equidigital number, since it uses as much as digits as its factorization.

21101320113257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 29.

Adding to 21101320113257 its reverse (75231102310112), we get a palindrome (96332422423369).

The spelling of 21101320113257 in words is "twenty-one trillion, one hundred one billion, three hundred twenty million, one hundred thirteen thousand, two hundred fifty-seven".