20540240 has 80 divisors (see below), whose sum is σ = 55913088. Its totient is φ = 6870528.

The previous prime is 20540239. The next prime is 20540243. The reversal of 20540240 is 4204502.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20540243) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23654 + ... + 24506.

Almost surely, 2^20540240 is an apocalyptic number.

20540240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20540240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27956544).

20540240 is an abundant number, since it is smaller than the sum of its proper divisors (35372848).

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

20540240 is a wasteful number, since it uses less digits than its factorization.

20540240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 916 (or 910 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 17.

The square root of 20540240 is about 4532.1341551194. The cubic root of 20540240 is about 273.8641413607.

Adding to 20540240 its reverse (4204502), we get a palindrome (24744742).

The spelling of 20540240 in words is "twenty million, five hundred forty thousand, two hundred forty".