20811330 has 40 divisors (see below), whose sum is σ = 55961532. Its totient is φ = 5549472.

The previous prime is 20811283. The next prime is 20811331. The reversal of 20811330 is 3311802.

It can be written as a sum of positive squares in 2 ways, for example, as 20331081 + 480249 = 4509^2 + 693^2 .

It is a super-2 number, since 2×20811330² = 866222912737800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20811331) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 12037 + ... + 13656.

Almost surely, 2^20811330 is an apocalyptic number.

20811330 is an abundant number, since it is smaller than the sum of its proper divisors (35150202).

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

20811330 is a wasteful number, since it uses less digits than its factorization.

20811330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25712 (or 25703 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 20811330 is about 4561.9436647113. The cubic root of 20811330 is about 275.0636987428.

The spelling of 20811330 in words is "twenty million, eight hundred eleven thousand, three hundred thirty".