20813120 has 56 divisors (see below), whose sum is σ = 49965864. Its totient is φ = 8257536.

The previous prime is 20813119. The next prime is 20813147. The reversal of 20813120 is 2131802.

It can be written as a sum of positive squares in 4 ways, for example, as 92416 + 20720704 = 304^2 + 4552^2 .

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 61592 + ... + 61928.

Almost surely, 2^20813120 is an apocalyptic number.

20813120 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 20813120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24982932).

20813120 is an abundant number, since it is smaller than the sum of its proper divisors (29152744).

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

20813120 is a wasteful number, since it uses less digits than its factorization.

20813120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 547 (or 537 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 20813120 is about 4562.1398487990. The cubic root of 20813120 is about 275.0715846701.

Adding to 20813120 its reverse (2131802), we get a palindrome (22944922).

The spelling of 20813120 in words is "twenty million, eight hundred thirteen thousand, one hundred twenty".