20623217 has 2 divisors, whose sum is σ = 20623218. Its totient is φ = 20623216.

The previous prime is 20623181. The next prime is 20623219. The reversal of 20623217 is 71232602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20106256 + 516961 = 4484^2 + 719^2 .

It is a cyclic number.

It is not a de Polignac number, because 20623217 - 2¹⁰ = 20622193 is a prime.

Together with 20623219, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_1307570 and since 20623217 and 1307570 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 20623192 and 20623201.

It is not a weakly prime, because it can be changed into another prime (20623219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10311608 + 10311609.

It is an arithmetic number, because the mean of its divisors is an integer number (10311609).

Almost surely, 2^20623217 is an apocalyptic number.

It is an amenable number.

20623217 is a deficient number, since it is larger than the sum of its proper divisors (1).

20623217 is an equidigital number, since it uses as much as digits as its factorization.

20623217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 20623217 is about 4541.2792250642. The cubic root of 20623217 is about 274.2324248403.

Adding to 20623217 its reverse (71232602), we get a palindrome (91855819).

The spelling of 20623217 in words is "twenty million, six hundred twenty-three thousand, two hundred seventeen".