20505500 has 24 divisors (see below), whose sum is σ = 44785104. Its totient is φ = 8202000.

The previous prime is 20505497. The next prime is 20505571. The reversal of 20505500 is 550502.

It is a happy number.

It is a congruent 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 7 ways as a sum of consecutive naturals, for example, 20006 + ... + 21005.

It is an arithmetic number, because the mean of its divisors is an integer number (1866046).

Almost surely, 2^20505500 is an apocalyptic number.

20505500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20505500 is an abundant number, since it is smaller than the sum of its proper divisors (24279604).

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

20505500 is a wasteful number, since it uses less digits than its factorization.

20505500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41030 (or 41018 counting only the distinct ones).

The product of its (nonzero) digits is 250, while the sum is 17.

The square root of 20505500 is about 4528.2999017291. The cubic root of 20505500 is about 273.7096574621.

The spelling of 20505500 in words is "twenty million, five hundred five thousand, five hundred".