21155055113 has 2 divisors, whose sum is σ = 21155055114. Its totient is φ = 21155055112.

The previous prime is 21155055109. The next prime is 21155055121. The reversal of 21155055113 is 31155055112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15963564409 + 5191490704 = 126347^2 + 72052^2 .

It is a cyclic number.

It is not a de Polignac number, because 21155055113 - 2² = 21155055109 is a prime.

It is not a weakly prime, because it can be changed into another prime (21155055143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577527556 + 10577527557.

It is an arithmetic number, because the mean of its divisors is an integer number (10577527557).

Almost surely, 2^21155055113 is an apocalyptic number.

It is an amenable number.

21155055113 is a deficient number, since it is larger than the sum of its proper divisors (1).

21155055113 is an equidigital number, since it uses as much as digits as its factorization.

21155055113 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3750, while the sum is 29.

Subtracting 21155055113 from its reverse (31155055112), we obtain a palindrome (9999999999).

The spelling of 21155055113 in words is "twenty-one billion, one hundred fifty-five million, fifty-five thousand, one hundred thirteen".