20205040 has 80 divisors (see below), whose sum is σ = 49996800. Its totient is φ = 7577856.

The previous prime is 20205023. The next prime is 20205041. The reversal of 20205040 is 4050202.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 20205040.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20205041) 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, 145291 + ... + 145429.

It is an arithmetic number, because the mean of its divisors is an integer number (624960).

Almost surely, 2^20205040 is an apocalyptic number.

20205040 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 20205040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24998400).

20205040 is an abundant number, since it is smaller than the sum of its proper divisors (29791760).

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

20205040 is a wasteful number, since it uses less digits than its factorization.

20205040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254 (or 248 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 13.

The square root of 20205040 is about 4495.0016685203. The cubic root of 20205040 is about 272.3662166295.

Adding to 20205040 its reverse (4050202), we get a palindrome (24255242).

The spelling of 20205040 in words is "twenty million, two hundred five thousand, forty".