20705197 has 2 divisors, whose sum is σ = 20705198. Its totient is φ = 20705196.

The previous prime is 20705177. The next prime is 20705203. The reversal of 20705197 is 79150702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18714276 + 1990921 = 4326^2 + 1411^2 .

It is a cyclic number.

It is not a de Polignac number, because 20705197 - 2²³ = 12316589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20705107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10352598 + 10352599.

It is an arithmetic number, because the mean of its divisors is an integer number (10352599).

Almost surely, 2^20705197 is an apocalyptic number.

It is an amenable number.

20705197 is a deficient number, since it is larger than the sum of its proper divisors (1).

20705197 is an equidigital number, since it uses as much as digits as its factorization.

20705197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4410, while the sum is 31.

The square root of 20705197 is about 4550.2963639745. The cubic root of 20705197 is about 274.5953144052.

Adding to 20705197 its reverse (79150702), we get a palindrome (99855899).

It can be divided in two parts, 20705 and 197, that added together give a palindrome (20902).

The spelling of 20705197 in words is "twenty million, seven hundred five thousand, one hundred ninety-seven".