20197109 has 2 divisors, whose sum is σ = 20197110. Its totient is φ = 20197108.

The previous prime is 20197103. The next prime is 20197123. The reversal of 20197109 is 90179102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19166884 + 1030225 = 4378^2 + 1015^2 .

It is a cyclic number.

It is not a de Polignac number, because 20197109 - 2⁸ = 20196853 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20197103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10098554 + 10098555.

It is an arithmetic number, because the mean of its divisors is an integer number (10098555).

Almost surely, 2^20197109 is an apocalyptic number.

It is an amenable number.

20197109 is a deficient number, since it is larger than the sum of its proper divisors (1).

20197109 is an equidigital number, since it uses as much as digits as its factorization.

20197109 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 20197109 is about 4494.1193798118. The cubic root of 20197109 is about 272.3305750410.

The spelling of 20197109 in words is "twenty million, one hundred ninety-seven thousand, one hundred nine".