20505018 has 8 divisors (see below), whose sum is σ = 41010048. Its totient is φ = 6835004.

The previous prime is 20505007. The next prime is 20505031. The reversal of 20505018 is 81050502.

It is a sphenic number, since it is the product of 3 distinct primes.

20505018 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 20504985 and 20505003.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1708746 + ... + 1708757.

It is an arithmetic number, because the mean of its divisors is an integer number (5126256).

Almost surely, 2^20505018 is an apocalyptic number.

20505018 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20505018 is a wasteful number, since it uses less digits than its factorization.

20505018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3417508.

The product of its (nonzero) digits is 400, while the sum is 21.

The square root of 20505018 is about 4528.2466805597. The cubic root of 20505018 is about 273.7075128490.

The spelling of 20505018 in words is "twenty million, five hundred five thousand, eighteen".