21131230117 has 2 divisors, whose sum is σ = 21131230118. Its totient is φ = 21131230116.

The previous prime is 21131230093. The next prime is 21131230123. The reversal of 21131230117 is 71103213112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21106568961 + 24661156 = 145281^2 + 4966^2 .

It is a cyclic number.

It is not a de Polignac number, because 21131230117 - 2⁷ = 21131229989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21131230177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565615058 + 10565615059.

It is an arithmetic number, because the mean of its divisors is an integer number (10565615059).

Almost surely, 2^21131230117 is an apocalyptic number.

It is an amenable number.

21131230117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131230117 is an equidigital number, since it uses as much as digits as its factorization.

21131230117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 22.

Adding to 21131230117 its reverse (71103213112), we get a palindrome (92234443229).

The spelling of 21131230117 in words is "twenty-one billion, one hundred thirty-one million, two hundred thirty thousand, one hundred seventeen".