20731156 has 12 divisors (see below), whose sum is σ = 36312192. Its totient is φ = 10356248.

The previous prime is 20731153. The next prime is 20731163. The reversal of 20731156 is 65113702.

It is a self number, because there is not a number n which added to its sum of digits gives 20731156.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20731153) 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 3 ways as a sum of consecutive naturals, for example, 5871 + ... + 8713.

It is an arithmetic number, because the mean of its divisors is an integer number (3026016).

Almost surely, 2^20731156 is an apocalyptic number.

It is an amenable number.

20731156 is a deficient number, since it is larger than the sum of its proper divisors (15581036).

20731156 is a wasteful number, since it uses less digits than its factorization.

20731156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4670 (or 4668 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 20731156 is about 4553.1479220425. The cubic root of 20731156 is about 274.7100238161.

Adding to 20731156 its reverse (65113702), we get a palindrome (85844858).

The spelling of 20731156 in words is "twenty million, seven hundred thirty-one thousand, one hundred fifty-six".