20187397 has 2 divisors, whose sum is σ = 20187398. Its totient is φ = 20187396.

The previous prime is 20187383. The next prime is 20187403. The reversal of 20187397 is 79378102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19838116 + 349281 = 4454^2 + 591^2 .

It is a cyclic number.

It is not a de Polignac number, because 20187397 - 2⁷ = 20187269 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20187317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10093698 + 10093699.

It is an arithmetic number, because the mean of its divisors is an integer number (10093699).

Almost surely, 2^20187397 is an apocalyptic number.

It is an amenable number.

20187397 is a deficient number, since it is larger than the sum of its proper divisors (1).

20187397 is an equidigital number, since it uses as much as digits as its factorization.

20187397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 20187397 is about 4493.0387267416. The cubic root of 20187397 is about 272.2869170007.

The spelling of 20187397 in words is "twenty million, one hundred eighty-seven thousand, three hundred ninety-seven".