20731136 has 36 divisors (see below), whose sum is σ = 42286272. Its totient is φ = 10139136.

The previous prime is 20731133. The next prime is 20731153. The reversal of 20731136 is 63113702.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20731133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11171 + ... + 12893.

Almost surely, 2^20731136 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20731136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21143136).

20731136 is an abundant number, since it is smaller than the sum of its proper divisors (21555136).

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

20731136 is an equidigital number, since it uses as much as digits as its factorization.

20731136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1786 (or 1772 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 23.

The square root of 20731136 is about 4553.1457257593. The cubic root of 20731136 is about 274.7099354756.

Adding to 20731136 its reverse (63113702), we get a palindrome (83844838).

The spelling of 20731136 in words is "twenty million, seven hundred thirty-one thousand, one hundred thirty-six".