20205420 has 24 divisors (see below), whose sum is σ = 56575344. Its totient is φ = 5388096.

The previous prime is 20205389. The next prime is 20205467. The reversal of 20205420 is 2450202.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 20205420.

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, 168319 + ... + 168438.

It is an arithmetic number, because the mean of its divisors is an integer number (2357306).

Almost surely, 2^20205420 is an apocalyptic number.

20205420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20205420 is an abundant number, since it is smaller than the sum of its proper divisors (36369924).

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

20205420 is a wasteful number, since it uses less digits than its factorization.

20205420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336769 (or 336767 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 15.

The square root of 20205420 is about 4495.0439374938. The cubic root of 20205420 is about 272.3679240998.

Adding to 20205420 its reverse (2450202), we get a palindrome (22655622).

The spelling of 20205420 in words is "twenty million, two hundred five thousand, four hundred twenty".