31131223 has 4 divisors (see below), whose sum is σ = 32135488. Its totient is φ = 30126960.

The previous prime is 31131211. The next prime is 31131227. The reversal of 31131223 is 32213113.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31131223 - 2⁹ = 31130711 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31131197 and 31131206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31131227) 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, 502086 + ... + 502147.

It is an arithmetic number, because the mean of its divisors is an integer number (8033872).

Almost surely, 2^31131223 is an apocalyptic number.

31131223 is a deficient number, since it is larger than the sum of its proper divisors (1004265).

31131223 is a wasteful number, since it uses less digits than its factorization.

31131223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1004264.

The product of its digits is 108, while the sum is 16.

The square root of 31131223 is about 5579.5360918270. The cubic root of 31131223 is about 314.5806900918.

Adding to 31131223 its reverse (32213113), we get a palindrome (63344336).

The spelling of 31131223 in words is "thirty-one million, one hundred thirty-one thousand, two hundred twenty-three".