20100505 has 16 divisors (see below), whose sum is σ = 25300224. Its totient is φ = 15301440.

The previous prime is 20100497. The next prime is 20100527. The reversal of 20100505 is 50500102.

It is not a de Polignac number, because 20100505 - 2³ = 20100497 is a prime.

It is a Duffinian number.

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 15 ways as a sum of consecutive naturals, for example, 31540 + ... + 32170.

It is an arithmetic number, because the mean of its divisors is an integer number (1581264).

Almost surely, 2^20100505 is an apocalyptic number.

It is an amenable number.

20100505 is a deficient number, since it is larger than the sum of its proper divisors (5199719).

20100505 is a wasteful number, since it uses less digits than its factorization.

20100505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 936.

The product of its (nonzero) digits is 50, while the sum is 13.

The square root of 20100505 is about 4483.3586740300. The cubic root of 20100505 is about 271.8956897101.

Adding to 20100505 its reverse (50500102), we get a palindrome (70600607).

The spelling of 20100505 in words is "twenty million, one hundred thousand, five hundred five".