21300099917 has 2 divisors, whose sum is σ = 21300099918. Its totient is φ = 21300099916.

The previous prime is 21300099883. The next prime is 21300099971. The reversal of 21300099917 is 71999000312.

Together with next prime (21300099971) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13356656041 + 7943443876 = 115571^2 + 89126^2 .

It is a cyclic number.

It is not a de Polignac number, because 21300099917 - 2¹⁴ = 21300083533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21300095917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650049958 + 10650049959.

It is an arithmetic number, because the mean of its divisors is an integer number (10650049959).

Almost surely, 2^21300099917 is an apocalyptic number.

It is an amenable number.

21300099917 is a deficient number, since it is larger than the sum of its proper divisors (1).

21300099917 is an equidigital number, since it uses as much as digits as its factorization.

21300099917 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30618, while the sum is 41.

The spelling of 21300099917 in words is "twenty-one billion, three hundred million, ninety-nine thousand, nine hundred seventeen".