21058218089 has 2 divisors, whose sum is σ = 21058218090. Its totient is φ = 21058218088.

The previous prime is 21058217953. The next prime is 21058218113. The reversal of 21058218089 is 98081285012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15577036864 + 5481181225 = 124808^2 + 74035^2 .

It is a cyclic number.

It is not a de Polignac number, because 21058218089 - 2¹² = 21058213993 is a prime.

It is not a weakly prime, because it can be changed into another prime (21058218289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10529109044 + 10529109045.

It is an arithmetic number, because the mean of its divisors is an integer number (10529109045).

Almost surely, 2^21058218089 is an apocalyptic number.

It is an amenable number.

21058218089 is a deficient number, since it is larger than the sum of its proper divisors (1).

21058218089 is an equidigital number, since it uses as much as digits as its factorization.

21058218089 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 92160, while the sum is 44.

The spelling of 21058218089 in words is "twenty-one billion, fifty-eight million, two hundred eighteen thousand, eighty-nine".