31133221 has 8 divisors (see below), whose sum is σ = 35619584. Its totient is φ = 26656560.

The previous prime is 31133213. The next prime is 31133231. The reversal of 31133221 is 12233113.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31133221 - 2³ = 31133213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31133195 and 31133204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31133231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6811 + ... + 10423.

It is an arithmetic number, because the mean of its divisors is an integer number (4452448).

Almost surely, 2^31133221 is an apocalyptic number.

It is an amenable number.

31133221 is a deficient number, since it is larger than the sum of its proper divisors (4486363).

31133221 is a wasteful number, since it uses less digits than its factorization.

31133221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4851.

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

The square root of 31133221 is about 5579.7151360979. The cubic root of 31133221 is about 314.5874198710.

Subtracting from 31133221 its product of digits (108), we obtain a palindrome (31133113).

Adding to 31133221 its reverse (12233113), we get a palindrome (43366334).

The spelling of 31133221 in words is "thirty-one million, one hundred thirty-three thousand, two hundred twenty-one".