20813841 has 20 divisors (see below), whose sum is σ = 31233972. Its totient is φ = 13812768.

The previous prime is 20813839. The next prime is 20813879. The reversal of 20813841 is 14831802.

It can be written as a sum of positive squares in 2 ways, for example, as 18740241 + 2073600 = 4329^2 + 1440^2 .

It is not a de Polignac number, because 20813841 - 2¹ = 20813839 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20813041) 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 19 ways as a sum of consecutive naturals, for example, 23295 + ... + 24171.

Almost surely, 2^20813841 is an apocalyptic number.

It is an amenable number.

20813841 is a deficient number, since it is larger than the sum of its proper divisors (10420131).

20813841 is an equidigital number, since it uses as much as digits as its factorization.

20813841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1182 (or 1173 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 20813841 is about 4562.2188680509. The cubic root of 20813841 is about 275.0747609410.

The spelling of 20813841 in words is "twenty million, eight hundred thirteen thousand, eight hundred forty-one".