20517223 has 2 divisors, whose sum is σ = 20517224. Its totient is φ = 20517222.

The previous prime is 20517221. The next prime is 20517229. The reversal of 20517223 is 32271502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20517223 - 2¹ = 20517221 is a prime.

Together with 20517221, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 20517194 and 20517203.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20517221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10258611 + 10258612.

It is an arithmetic number, because the mean of its divisors is an integer number (10258612).

Almost surely, 2^20517223 is an apocalyptic number.

20517223 is a deficient number, since it is larger than the sum of its proper divisors (1).

20517223 is an equidigital number, since it uses as much as digits as its factorization.

20517223 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 20517223 is about 4529.5941319284. The cubic root of 20517223 is about 273.7618074875.

Adding to 20517223 its reverse (32271502), we get a palindrome (52788725).

The spelling of 20517223 in words is "twenty million, five hundred seventeen thousand, two hundred twenty-three".