21131657269 has 2 divisors, whose sum is σ = 21131657270. Its totient is φ = 21131657268.

The previous prime is 21131657249. The next prime is 21131657293. The reversal of 21131657269 is 96275613112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12885201169 + 8246456100 = 113513^2 + 90810^2 .

It is a cyclic number.

It is not a de Polignac number, because 21131657269 - 2¹¹ = 21131655221 is a prime.

It is a super-2 number, since 2×21131657269² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21131657249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565828634 + 10565828635.

It is an arithmetic number, because the mean of its divisors is an integer number (10565828635).

Almost surely, 2^21131657269 is an apocalyptic number.

It is an amenable number.

21131657269 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131657269 is an equidigital number, since it uses as much as digits as its factorization.

21131657269 is an evil number, because the sum of its binary digits is even.

The product of its digits is 136080, while the sum is 43.

The spelling of 21131657269 in words is "twenty-one billion, one hundred thirty-one million, six hundred fifty-seven thousand, two hundred sixty-nine".