21320203109 has 2 divisors, whose sum is σ = 21320203110. Its totient is φ = 21320203108.

The previous prime is 21320203103. The next prime is 21320203123. The reversal of 21320203109 is 90130202312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20648253025 + 671950084 = 143695^2 + 25922^2 .

It is a cyclic number.

It is not a de Polignac number, because 21320203109 - 2¹² = 21320199013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21320203103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660101554 + 10660101555.

It is an arithmetic number, because the mean of its divisors is an integer number (10660101555).

Almost surely, 2^21320203109 is an apocalyptic number.

It is an amenable number.

21320203109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320203109 is an equidigital number, since it uses as much as digits as its factorization.

21320203109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 23.

The spelling of 21320203109 in words is "twenty-one billion, three hundred twenty million, two hundred three thousand, one hundred nine".