21131133449 has 2 divisors, whose sum is σ = 21131133450. Its totient is φ = 21131133448.

The previous prime is 21131133349. The next prime is 21131133481. The reversal of 21131133449 is 94433113112.

It is an a-pointer prime, because the next prime (21131133481) can be obtained adding 21131133449 to its sum of digits (32).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21116449225 + 14684224 = 145315^2 + 3832^2 .

It is a cyclic number.

It is not a de Polignac number, because 21131133449 - 2⁸ = 21131133193 is a prime.

It is not a weakly prime, because it can be changed into another prime (21131133349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565566724 + 10565566725.

It is an arithmetic number, because the mean of its divisors is an integer number (10565566725).

Almost surely, 2^21131133449 is an apocalyptic number.

It is an amenable number.

21131133449 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131133449 is an equidigital number, since it uses as much as digits as its factorization.

21131133449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 32.

The spelling of 21131133449 in words is "twenty-one billion, one hundred thirty-one million, one hundred thirty-three thousand, four hundred forty-nine".