20505306 has 8 divisors (see below), whose sum is σ = 41010624. Its totient is φ = 6835100.

The previous prime is 20505269. The next prime is 20505307. The reversal of 20505306 is 60350502.

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

20505306 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (20505307) by changing a digit.

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, 1708770 + ... + 1708781.

It is an arithmetic number, because the mean of its divisors is an integer number (5126328).

Almost surely, 2^20505306 is an apocalyptic number.

20505306 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.

20505306 is a wasteful number, since it uses less digits than its factorization.

20505306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3417556.

The product of its (nonzero) digits is 900, while the sum is 21.

The square root of 20505306 is about 4528.2784808357. The cubic root of 20505306 is about 273.7087942816.

Adding to 20505306 its reverse (60350502), we get a palindrome (80855808).

The spelling of 20505306 in words is "twenty million, five hundred five thousand, three hundred six".