20997173117 has 2 divisors, whose sum is σ = 20997173118. Its totient is φ = 20997173116.

The previous prime is 20997173111. The next prime is 20997173129. The reversal of 20997173117 is 71137179902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14164332196 + 6832840921 = 119014^2 + 82661^2 .

It is a cyclic number.

It is not a de Polignac number, because 20997173117 - 2²⁴ = 20980395901 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20997173111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10498586558 + 10498586559.

It is an arithmetic number, because the mean of its divisors is an integer number (10498586559).

Almost surely, 2^20997173117 is an apocalyptic number.

It is an amenable number.

20997173117 is a deficient number, since it is larger than the sum of its proper divisors (1).

20997173117 is an equidigital number, since it uses as much as digits as its factorization.

20997173117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 166698, while the sum is 47.

The spelling of 20997173117 in words is "twenty billion, nine hundred ninety-seven million, one hundred seventy-three thousand, one hundred seventeen".