20505218 has 16 divisors (see below), whose sum is σ = 32716320. Its totient is φ = 9611136.

The previous prime is 20505217. The next prime is 20505227. The reversal of 20505218 is 81250502.

It is a junction number, because it is equal to n+sod(n) for n = 20505193 and 20505202.

It is not an unprimeable number, because it can be changed into a prime (20505217) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 905 + ... + 6467.

It is an arithmetic number, because the mean of its divisors is an integer number (2044770).

Almost surely, 2^20505218 is an apocalyptic number.

20505218 is a deficient number, since it is larger than the sum of its proper divisors (12211102).

20505218 is a wasteful number, since it uses less digits than its factorization.

20505218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5681.

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 20505218 is about 4528.2687641084. The cubic root of 20505218 is about 273.7084027340.

The spelling of 20505218 in words is "twenty million, five hundred five thousand, two hundred eighteen".