21113352509 has 2 divisors, whose sum is σ = 21113352510. Its totient is φ = 21113352508.

The previous prime is 21113352479. The next prime is 21113352569. The reversal of 21113352509 is 90525331112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19993111609 + 1120240900 = 141397^2 + 33470^2 .

It is a cyclic number.

It is not a de Polignac number, because 21113352509 - 2²⁴ = 21096575293 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21113352569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556676254 + 10556676255.

It is an arithmetic number, because the mean of its divisors is an integer number (10556676255).

Almost surely, 2^21113352509 is an apocalyptic number.

It is an amenable number.

21113352509 is a deficient number, since it is larger than the sum of its proper divisors (1).

21113352509 is an equidigital number, since it uses as much as digits as its factorization.

21113352509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8100, while the sum is 32.

The spelling of 21113352509 in words is "twenty-one billion, one hundred thirteen million, three hundred fifty-two thousand, five hundred nine".