20533240 has 64 divisors (see below), whose sum is σ = 56871360. Its totient is φ = 6497280.

The previous prime is 20533223. The next prime is 20533241. The reversal of 20533240 is 4233502.

It is a super-2 number, since 2×20533240² = 843227889795200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20533241) 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, 820 + ... + 6460.

It is an arithmetic number, because the mean of its divisors is an integer number (888615).

Almost surely, 2^20533240 is an apocalyptic number.

20533240 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 20533240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28435680).

20533240 is an abundant number, since it is smaller than the sum of its proper divisors (36338120).

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

20533240 is a wasteful number, since it uses less digits than its factorization.

20533240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5672 (or 5668 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 19.

The square root of 20533240 is about 4531.3618262063. The cubic root of 20533240 is about 273.8330273652.

Adding to 20533240 its reverse (4233502), we get a palindrome (24766742).

The spelling of 20533240 in words is "twenty million, five hundred thirty-three thousand, two hundred forty".