21232220257 has 2 divisors, whose sum is σ = 21232220258. Its totient is φ = 21232220256.

The previous prime is 21232220183. The next prime is 21232220279. The reversal of 21232220257 is 75202223212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21036891681 + 195328576 = 145041^2 + 13976^2 .

It is a cyclic number.

It is not a de Polignac number, because 21232220257 - 2¹¹ = 21232218209 is a prime.

It is a super-2 number, since 2×21232220257² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21232220857) 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, 10616110128 + 10616110129.

It is an arithmetic number, because the mean of its divisors is an integer number (10616110129).

Almost surely, 2^21232220257 is an apocalyptic number.

It is an amenable number.

21232220257 is a deficient number, since it is larger than the sum of its proper divisors (1).

21232220257 is an equidigital number, since it uses as much as digits as its factorization.

21232220257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6720, while the sum is 28.

Adding to 21232220257 its reverse (75202223212), we get a palindrome (96434443469).

The spelling of 21232220257 in words is "twenty-one billion, two hundred thirty-two million, two hundred twenty thousand, two hundred fifty-seven".