21031222220257 has 2 divisors, whose sum is σ = 21031222220258. Its totient is φ = 21031222220256.

The previous prime is 21031222220237. The next prime is 21031222220329. The reversal of 21031222220257 is 75202222213012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17766258720016 + 3264963500241 = 4215004^2 + 1806921^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21031222220257 is a prime.

It is a super-2 number, since 2×21031222220257² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21031222220237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515611110128 + 10515611110129.

It is an arithmetic number, because the mean of its divisors is an integer number (10515611110129).

Almost surely, 2^{21031222220257} is an apocalyptic number.

It is an amenable number.

21031222220257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21031222220257 is an equidigital number, since it uses as much as digits as its factorization.

21031222220257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13440, while the sum is 31.

Adding to 21031222220257 its reverse (75202222213012), we get a palindrome (96233444433269).

The spelling of 21031222220257 in words is "twenty-one trillion, thirty-one billion, two hundred twenty-two million, two hundred twenty thousand, two hundred fifty-seven".