21131342249 has 2 divisors, whose sum is σ = 21131342250. Its totient is φ = 21131342248.

The previous prime is 21131342213. The next prime is 21131342257. The reversal of 21131342249 is 94224313112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20841253225 + 290089024 = 144365^2 + 17032^2 .

It is a cyclic number.

It is not a de Polignac number, because 21131342249 - 2⁸ = 21131341993 is a prime.

It is not a weakly prime, because it can be changed into another prime (21131362249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565671124 + 10565671125.

It is an arithmetic number, because the mean of its divisors is an integer number (10565671125).

Almost surely, 2^21131342249 is an apocalyptic number.

It is an amenable number.

21131342249 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131342249 is an equidigital number, since it uses as much as digits as its factorization.

21131342249 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 32.

The spelling of 21131342249 in words is "twenty-one billion, one hundred thirty-one million, three hundred forty-two thousand, two hundred forty-nine".