20509117 has 2 divisors, whose sum is σ = 20509118. Its totient is φ = 20509116.

The previous prime is 20509109. The next prime is 20509127. The reversal of 20509117 is 71190502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14584761 + 5924356 = 3819^2 + 2434^2 .

It is a cyclic number.

It is not a de Polignac number, because 20509117 - 2³ = 20509109 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20509091 and 20509100.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20509127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10254558 + 10254559.

It is an arithmetic number, because the mean of its divisors is an integer number (10254559).

Almost surely, 2^20509117 is an apocalyptic number.

It is an amenable number.

20509117 is a deficient number, since it is larger than the sum of its proper divisors (1).

20509117 is an equidigital number, since it uses as much as digits as its factorization.

20509117 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 630, while the sum is 25.

The square root of 20509117 is about 4528.6992613774. The cubic root of 20509117 is about 273.7257498865.

Adding to 20509117 its reverse (71190502), we get a palindrome (91699619).

The spelling of 20509117 in words is "twenty million, five hundred nine thousand, one hundred seventeen".