20109197 has 2 divisors, whose sum is σ = 20109198. Its totient is φ = 20109196.

The previous prime is 20109191. The next prime is 20109211. The reversal of 20109197 is 79190102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14638276 + 5470921 = 3826^2 + 2339^2 .

It is a cyclic number.

It is not a de Polignac number, because 20109197 - 2⁸ = 20108941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20109191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10054598 + 10054599.

It is an arithmetic number, because the mean of its divisors is an integer number (10054599).

Almost surely, 2^20109197 is an apocalyptic number.

It is an amenable number.

20109197 is a deficient number, since it is larger than the sum of its proper divisors (1).

20109197 is an equidigital number, since it uses as much as digits as its factorization.

20109197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1134, while the sum is 29.

The square root of 20109197 is about 4484.3279318087. The cubic root of 20109197 is about 271.9348757366.

Adding to 20109197 its reverse (79190102), we get a palindrome (99299299).

The spelling of 20109197 in words is "twenty million, one hundred nine thousand, one hundred ninety-seven".