20634217 has 2 divisors, whose sum is σ = 20634218. Its totient is φ = 20634216.

The previous prime is 20634161. The next prime is 20634221. The reversal of 20634217 is 71243602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15139881 + 5494336 = 3891^2 + 2344^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20634217 is a prime.

It is a super-2 number, since 2×20634217² = 851541822406178, which contains 22 as substring.

It is equal to p_1308238 and since 20634217 and 1308238 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 = 20634191 and 20634200.

It is not a weakly prime, because it can be changed into another prime (20634017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10317108 + 10317109.

It is an arithmetic number, because the mean of its divisors is an integer number (10317109).

Almost surely, 2^20634217 is an apocalyptic number.

It is an amenable number.

20634217 is a deficient number, since it is larger than the sum of its proper divisors (1).

20634217 is an equidigital number, since it uses as much as digits as its factorization.

20634217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 20634217 is about 4542.4901761039. The cubic root of 20634217 is about 274.2811728203.

Adding to 20634217 its reverse (71243602), we get a palindrome (91877819).

The spelling of 20634217 in words is "twenty million, six hundred thirty-four thousand, two hundred seventeen".