20198917 has 2 divisors, whose sum is σ = 20198918. Its totient is φ = 20198916.

The previous prime is 20198911. The next prime is 20198921. The reversal of 20198917 is 71989102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12630916 + 7568001 = 3554^2 + 2751^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20198917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20198911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10099458 + 10099459.

It is an arithmetic number, because the mean of its divisors is an integer number (10099459).

Almost surely, 2^20198917 is an apocalyptic number.

It is an amenable number.

20198917 is a deficient number, since it is larger than the sum of its proper divisors (1).

20198917 is an equidigital number, since it uses as much as digits as its factorization.

20198917 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 20198917 is about 4494.3205270652. The cubic root of 20198917 is about 272.3387009398.

It can be divided in two parts, 20198 and 917, that added together give a triangular number (21115 = T₂₀₅).

The spelling of 20198917 in words is "twenty million, one hundred ninety-eight thousand, nine hundred seventeen".