20506117 has 4 divisors (see below), whose sum is σ = 20531916. Its totient is φ = 20480320.

The previous prime is 20506093. The next prime is 20506151. The reversal of 20506117 is 71160502.

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 2307361 + 18198756 = 1519^2 + 4266^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20506117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20506417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11668 + ... + 13309.

It is an arithmetic number, because the mean of its divisors is an integer number (5132979).

Almost surely, 2^20506117 is an apocalyptic number.

It is an amenable number.

20506117 is a deficient number, since it is larger than the sum of its proper divisors (25799).

20506117 is an equidigital number, since it uses as much as digits as its factorization.

20506117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25798.

The product of its (nonzero) digits is 420, while the sum is 22.

The square root of 20506117 is about 4528.3680283299. The cubic root of 20506117 is about 273.7124026957.

Adding to 20506117 its reverse (71160502), we get a palindrome (91666619).

The spelling of 20506117 in words is "twenty million, five hundred six thousand, one hundred seventeen".