20117513 has 4 divisors (see below), whose sum is σ = 21665028. Its totient is φ = 18570000.

The previous prime is 20117497. The next prime is 20117519. The reversal of 20117513 is 31571102.

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 3892729 + 16224784 = 1973^2 + 4028^2 .

It is a cyclic number.

It is not a de Polignac number, because 20117513 - 2⁴ = 20117497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20117519) 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, 773738 + ... + 773763.

It is an arithmetic number, because the mean of its divisors is an integer number (5416257).

Almost surely, 2^20117513 is an apocalyptic number.

It is an amenable number.

20117513 is a deficient number, since it is larger than the sum of its proper divisors (1547515).

20117513 is a wasteful number, since it uses less digits than its factorization.

20117513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1547514.

The product of its (nonzero) digits is 210, while the sum is 20.

The square root of 20117513 is about 4485.2550652109. The cubic root of 20117513 is about 271.9723560790.

Adding to 20117513 its reverse (31571102), we get a palindrome (51688615).

The spelling of 20117513 in words is "twenty million, one hundred seventeen thousand, five hundred thirteen".