20205380 has 24 divisors (see below), whose sum is σ = 45695832. Its totient is φ = 7460352.

The previous prime is 20205377. The next prime is 20205389. The reversal of 20205380 is 8350202.

It can be written as a sum of positive squares in 4 ways, for example, as 295936 + 19909444 = 544^2 + 4462^2 .

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

It is not an unprimeable number, because it can be changed into a prime (20205389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38597 + ... + 39116.

It is an arithmetic number, because the mean of its divisors is an integer number (1903993).

Almost surely, 2^20205380 is an apocalyptic number.

20205380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20205380 is an abundant number, since it is smaller than the sum of its proper divisors (25490452).

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

20205380 is a wasteful number, since it uses less digits than its factorization.

20205380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77735 (or 77733 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 20205380 is about 4495.0394881469. The cubic root of 20205380 is about 272.3677443671.

Adding to 20205380 its reverse (8350202), we get a palindrome (28555582).

The spelling of 20205380 in words is "twenty million, two hundred five thousand, three hundred eighty".