20215505 has 16 divisors (see below), whose sum is σ = 26002944. Its totient is φ = 15048000.

The previous prime is 20215463. The next prime is 20215513. The reversal of 20215505 is 50551202.

It is not a de Polignac number, because 20215505 - 2¹⁸ = 19953361 is a prime.

It is a Duffinian number.

It is a Curzon 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, 1880 + ... + 6630.

It is an arithmetic number, because the mean of its divisors is an integer number (1625184).

Almost surely, 2^20215505 is an apocalyptic number.

It is an amenable number.

20215505 is a deficient number, since it is larger than the sum of its proper divisors (5787439).

20215505 is a wasteful number, since it uses less digits than its factorization.

20215505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4816.

The product of its (nonzero) digits is 500, while the sum is 20.

The square root of 20215505 is about 4496.1655885877. The cubic root of 20215505 is about 272.4132316400.

Adding to 20215505 its reverse (50551202), we get a palindrome (70766707).

The spelling of 20215505 in words is "twenty million, two hundred fifteen thousand, five hundred five".