20731131 has 12 divisors (see below), whose sum is σ = 30254952. Its totient is φ = 13677696.

The previous prime is 20731129. The next prime is 20731133. The reversal of 20731131 is 13113702.

It is an interprime number because it is at equal distance from previous prime (20731129) and next prime (20731133).

It is not a de Polignac number, because 20731131 - 2¹ = 20731129 is a prime.

It is a super-2 number, since 2×20731131² = 859559585078322, which contains 22 as substring.

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 11 ways as a sum of consecutive naturals, for example, 11001 + ... + 12746.

It is an arithmetic number, because the mean of its divisors is an integer number (2521246).

Almost surely, 2^20731131 is an apocalyptic number.

20731131 is a deficient number, since it is larger than the sum of its proper divisors (9523821).

20731131 is a wasteful number, since it uses less digits than its factorization.

20731131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23850 (or 23847 counting only the distinct ones).

The product of its (nonzero) digits is 126, while the sum is 18.

The square root of 20731131 is about 4553.1451766883. The cubic root of 20731131 is about 274.7099133905.

Adding to 20731131 its reverse (13113702), we get a palindrome (33844833).

The spelling of 20731131 in words is "twenty million, seven hundred thirty-one thousand, one hundred thirty-one".