20145240 has 128 divisors (see below), whose sum is σ = 70156800. Its totient is φ = 5132160.

The previous prime is 20145233. The next prime is 20145241. The reversal of 20145240 is 4254102.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20145241) 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 31 ways as a sum of consecutive naturals, for example, 24435 + ... + 25245.

It is an arithmetic number, because the mean of its divisors is an integer number (548100).

Almost surely, 2^20145240 is an apocalyptic number.

20145240 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 20145240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35078400).

20145240 is an abundant number, since it is smaller than the sum of its proper divisors (50011560).

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

20145240 is a wasteful number, since it uses less digits than its factorization.

20145240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 854 (or 844 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 20145240 is about 4488.3449065329. The cubic root of 20145240 is about 272.0972475224.

Adding to 20145240 its reverse (4254102), we get a palindrome (24399342).

The spelling of 20145240 in words is "twenty million, one hundred forty-five thousand, two hundred forty".