20145840 has 160 divisors (see below), whose sum is σ = 73495296. Its totient is φ = 4500480.

The previous prime is 20145821. The next prime is 20145847. The reversal of 20145840 is 4854102.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 20145840.

It is not an unprimeable number, because it can be changed into a prime (20145847) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34027 + ... + 34613.

Almost surely, 2^20145840 is an apocalyptic number.

20145840 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 20145840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36747648).

20145840 is an abundant number, since it is smaller than the sum of its proper divisors (53349456).

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

20145840 is a wasteful number, since it uses less digits than its factorization.

20145840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 627 (or 621 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 20145840 is about 4488.4117458183. The cubic root of 20145840 is about 272.0999488509.

Adding to 20145840 its reverse (4854102), we get a palindrome (24999942).

The spelling of 20145840 in words is "twenty million, one hundred forty-five thousand, eight hundred forty".