31121131 has 4 divisors (see below), whose sum is σ = 31137832. Its totient is φ = 31104432.

The previous prime is 31121087. The next prime is 31121137. The reversal of 31121131 is 13112113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13112113 = 7 ⋅1873159.

It is a cyclic number.

It is not a de Polignac number, because 31121131 - 2⁹ = 31120619 is a prime.

It is a super-2 number, since 2×31121131² = 1937049589438322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31121137) 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, 5145 + ... + 9418.

It is an arithmetic number, because the mean of its divisors is an integer number (7784458).

Almost surely, 2^31121131 is an apocalyptic number.

31121131 is a deficient number, since it is larger than the sum of its proper divisors (16701).

31121131 is a wasteful number, since it uses less digits than its factorization.

31121131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16700.

The product of its digits is 18, while the sum is 13.

The square root of 31121131 is about 5578.6316422578. The cubic root of 31121131 is about 314.5466932322.

Adding to 31121131 its reverse (13112113), we get a palindrome (44233244).

The spelling of 31121131 in words is "thirty-one million, one hundred twenty-one thousand, one hundred thirty-one".