20081540 has 12 divisors (see below), whose sum is σ = 42171276. Its totient is φ = 8032608.

The previous prime is 20081531. The next prime is 20081561. The reversal of 20081540 is 4518002.

It can be written as a sum of positive squares in 2 ways, for example, as 2709316 + 17372224 = 1646^2 + 4168^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1004077 = 20081540 / (2 + 0 + 0 + 8 + 1 + 5 + 4 + 0).

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 502019 + ... + 502058.

It is an arithmetic number, because the mean of its divisors is an integer number (3514273).

Almost surely, 2^20081540 is an apocalyptic number.

20081540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20081540 is an abundant number, since it is smaller than the sum of its proper divisors (22089736).

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

20081540 is a wasteful number, since it uses less digits than its factorization.

20081540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1004086 (or 1004084 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 20081540 is about 4481.2431310965. The cubic root of 20081540 is about 271.8101508254.

Adding to 20081540 its reverse (4518002), we get a palindrome (24599542).

The spelling of 20081540 in words is "twenty million, eighty-one thousand, five hundred forty".