20805500 has 24 divisors (see below), whose sum is σ = 45440304. Its totient is φ = 8322000.

The previous prime is 20805497. The next prime is 20805503. The reversal of 20805500 is 550802.

It is an interprime number because it is at equal distance from previous prime (20805497) and next prime (20805503).

It is a hoax number, since the sum of its digits (20) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20805503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20306 + ... + 21305.

It is an arithmetic number, because the mean of its divisors is an integer number (1893346).

Almost surely, 2^20805500 is an apocalyptic number.

20805500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20805500 is an abundant number, since it is smaller than the sum of its proper divisors (24634804).

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

20805500 is a wasteful number, since it uses less digits than its factorization.

20805500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41630 (or 41618 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 20805500 is about 4561.3046379298. The cubic root of 20805500 is about 275.0380112747.

The spelling of 20805500 in words is "twenty million, eight hundred five thousand, five hundred".