20881520 has 80 divisors (see below), whose sum is σ = 53969760. Its totient is φ = 7449600.

The previous prime is 20881501. The next prime is 20881529. The reversal of 20881520 is 2518802.

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 20881520.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20881529) 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 15 ways as a sum of consecutive naturals, for example, 53486 + ... + 53874.

It is an arithmetic number, because the mean of its divisors is an integer number (674622).

Almost surely, 2^20881520 is an apocalyptic number.

20881520 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 20881520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26984880).

20881520 is an abundant number, since it is smaller than the sum of its proper divisors (33088240).

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

20881520 is a wasteful number, since it uses less digits than its factorization.

20881520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 474 (or 468 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 26.

The square root of 20881520 is about 4569.6301819732. The cubic root of 20881520 is about 275.3725858802.

The spelling of 20881520 in words is "twenty million, eight hundred eighty-one thousand, five hundred twenty".