20197997 has 2 divisors, whose sum is σ = 20197998. Its totient is φ = 20197996.

The previous prime is 20197987. The next prime is 20198033. The reversal of 20197997 is 79979102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14600041 + 5597956 = 3821^2 + 2366^2 .

It is a cyclic number.

It is not a de Polignac number, because 20197997 - 2⁴ = 20197981 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20197907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10098998 + 10098999.

It is an arithmetic number, because the mean of its divisors is an integer number (10098999).

Almost surely, 2^20197997 is an apocalyptic number.

It is an amenable number.

20197997 is a deficient number, since it is larger than the sum of its proper divisors (1).

20197997 is an equidigital number, since it uses as much as digits as its factorization.

20197997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 71442, while the sum is 44.

The square root of 20197997 is about 4494.2181744993. The cubic root of 20197997 is about 272.3345661404.

The spelling of 20197997 in words is "twenty million, one hundred ninety-seven thousand, nine hundred ninety-seven".