20820520 has 128 divisors (see below), whose sum is σ = 57853440. Its totient is φ = 6589440.

The previous prime is 20820511. The next prime is 20820533. The reversal of 20820520 is 2502802.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 341290 + ... + 341350.

It is an arithmetic number, because the mean of its divisors is an integer number (451980).

Almost surely, 2^20820520 is an apocalyptic number.

20820520 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 20820520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28926720).

20820520 is an abundant number, since it is smaller than the sum of its proper divisors (37032920).

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

20820520 is a wasteful number, since it uses less digits than its factorization.

20820520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155 (or 151 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 20820520 is about 4562.9507996471. The cubic root of 20820520 is about 275.1041809128.

The spelling of 20820520 in words is "twenty million, eight hundred twenty thousand, five hundred twenty".