20501280 has 144 divisors (see below), whose sum is σ = 73120320. Its totient is φ = 5220864.

The previous prime is 20501267. The next prime is 20501281. The reversal of 20501280 is 8210502.

It is a tau number, because it is divible by the number of its divisors (144).

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 (20501281) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 32811 + ... + 33429.

It is an arithmetic number, because the mean of its divisors is an integer number (507780).

Almost surely, 2^20501280 is an apocalyptic number.

20501280 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 20501280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36560160).

20501280 is an abundant number, since it is smaller than the sum of its proper divisors (52619040).

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

20501280 is a wasteful number, since it uses less digits than its factorization.

20501280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663 (or 652 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 20501280 is about 4527.8339192157. The cubic root of 20501280 is about 273.6908798333.

Adding to 20501280 its reverse (8210502), we get a palindrome (28711782).

The spelling of 20501280 in words is "twenty million, five hundred one thousand, two hundred eighty".