21311011109 has 2 divisors, whose sum is σ = 21311011110. Its totient is φ = 21311011108.

The previous prime is 21311011091. The next prime is 21311011187. The reversal of 21311011109 is 90111011312.

It is a happy number.

Together with previous prime (21311011091) 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., 13901589025 + 7409422084 = 117905^2 + 86078^2 .

It is a cyclic number.

It is not a de Polignac number, because 21311011109 - 2²⁰ = 21309962533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21311011409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655505554 + 10655505555.

It is an arithmetic number, because the mean of its divisors is an integer number (10655505555).

Almost surely, 2^21311011109 is an apocalyptic number.

It is an amenable number.

21311011109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311011109 is an equidigital number, since it uses as much as digits as its factorization.

21311011109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54, while the sum is 20.

The spelling of 21311011109 in words is "twenty-one billion, three hundred eleven million, eleven thousand, one hundred nine".