20505113 has 4 divisors (see below), whose sum is σ = 20941440. Its totient is φ = 20068788.

The previous prime is 20505103. The next prime is 20505127. The reversal of 20505113 is 31150502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31150502 = 2 ⋅15575251.

It is a cyclic number.

It is not a de Polignac number, because 20505113 - 2⁴ = 20505097 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20505091 and 20505100.

It is not an unprimeable number, because it can be changed into a prime (20505103) 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, 218093 + ... + 218186.

It is an arithmetic number, because the mean of its divisors is an integer number (5235360).

Almost surely, 2^20505113 is an apocalyptic number.

It is an amenable number.

20505113 is a deficient number, since it is larger than the sum of its proper divisors (436327).

20505113 is an equidigital number, since it uses as much as digits as its factorization.

20505113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 436326.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 20505113 is about 4528.2571702588. The cubic root of 20505113 is about 273.7079355451.

Adding to 20505113 its reverse (31150502), we get a palindrome (51655615).

The spelling of 20505113 in words is "twenty million, five hundred five thousand, one hundred thirteen".