20866897 has 2 divisors, whose sum is σ = 20866898. Its totient is φ = 20866896.

The previous prime is 20866877. The next prime is 20866907. The reversal of 20866897 is 79866802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19793601 + 1073296 = 4449^2 + 1036^2 .

It is a cyclic number.

It is not a de Polignac number, because 20866897 - 2¹¹ = 20864849 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20866847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10433448 + 10433449.

It is an arithmetic number, because the mean of its divisors is an integer number (10433449).

Almost surely, 2^20866897 is an apocalyptic number.

It is an amenable number.

20866897 is a deficient number, since it is larger than the sum of its proper divisors (1).

20866897 is an equidigital number, since it uses as much as digits as its factorization.

20866897 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 290304, while the sum is 46.

The square root of 20866897 is about 4568.0298816886. The cubic root of 20866897 is about 275.3082911729.

The spelling of 20866897 in words is "twenty million, eight hundred sixty-six thousand, eight hundred ninety-seven".