20005217 has 4 divisors (see below), whose sum is σ = 20077716. Its totient is φ = 19932720.

The previous prime is 20005213. The next prime is 20005231. The reversal of 20005217 is 71250002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3876961 + 16128256 = 1969^2 + 4016^2 .

It is a cyclic number.

It is not a de Polignac number, because 20005217 - 2² = 20005213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20005195 and 20005204.

It is not an unprimeable number, because it can be changed into a prime (20005213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35834 + ... + 36387.

It is an arithmetic number, because the mean of its divisors is an integer number (5019429).

Almost surely, 2^20005217 is an apocalyptic number.

It is an amenable number.

20005217 is a deficient number, since it is larger than the sum of its proper divisors (72499).

20005217 is an equidigital number, since it uses as much as digits as its factorization.

20005217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72498.

The product of its (nonzero) digits is 140, while the sum is 17.

The square root of 20005217 is about 4472.7191952994. The cubic root of 20005217 is about 271.4653614688.

Adding to 20005217 its reverse (71250002), we get a palindrome (91255219).

The spelling of 20005217 in words is "twenty million, five thousand, two hundred seventeen".