20897497 has 2 divisors, whose sum is σ = 20897498. Its totient is φ = 20897496.

The previous prime is 20897483. The next prime is 20897509. The reversal of 20897497 is 79479802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14220441 + 6677056 = 3771^2 + 2584^2 .

It is a cyclic number.

It is not a de Polignac number, because 20897497 - 2¹⁹ = 20373209 is a prime.

It is not a weakly prime, because it can be changed into another prime (20897477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10448748 + 10448749.

It is an arithmetic number, because the mean of its divisors is an integer number (10448749).

Almost surely, 2^20897497 is an apocalyptic number.

It is an amenable number.

20897497 is a deficient number, since it is larger than the sum of its proper divisors (1).

20897497 is an equidigital number, since it uses as much as digits as its factorization.

20897497 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 254016, while the sum is 46.

The square root of 20897497 is about 4571.3780198098. The cubic root of 20897497 is about 275.4427995778.

The spelling of 20897497 in words is "twenty million, eight hundred ninety-seven thousand, four hundred ninety-seven".