20131031 has 2 divisors, whose sum is σ = 20131032. Its totient is φ = 20131030.

The previous prime is 20131019. The next prime is 20131061. The reversal of 20131031 is 13013102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20131031 - 2²² = 15936727 is a prime.

It is a super-2 number, since 2×20131031² = 810516818245922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20131061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10065515 + 10065516.

It is an arithmetic number, because the mean of its divisors is an integer number (10065516).

Almost surely, 2^20131031 is an apocalyptic number.

20131031 is a deficient number, since it is larger than the sum of its proper divisors (1).

20131031 is an equidigital number, since it uses as much as digits as its factorization.

20131031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 20131031 is about 4486.7617498592. The cubic root of 20131031 is about 272.0332598818.

Adding to 20131031 its reverse (13013102), we get a palindrome (33144133).

The spelling of 20131031 in words is "twenty million, one hundred thirty-one thousand, thirty-one".