31443221 has 8 divisors (see below), whose sum is σ = 32590080. Its totient is φ = 30300592.

The previous prime is 31443211. The next prime is 31443239. The reversal of 31443221 is 12234413.

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

It is a de Polignac number, because none of the positive numbers 2^k-31443221 is a prime.

It is a super-2 number, since 2×31443221² = 1977352293709682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31443193 and 31443202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31443211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27956 + ... + 29058.

It is an arithmetic number, because the mean of its divisors is an integer number (4073760).

Almost surely, 2^31443221 is an apocalyptic number.

It is an amenable number.

31443221 is a deficient number, since it is larger than the sum of its proper divisors (1146859).

31443221 is a wasteful number, since it uses less digits than its factorization.

31443221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2115.

The product of its digits is 576, while the sum is 20.

The square root of 31443221 is about 5607.4255233574. The cubic root of 31443221 is about 315.6281109519.

Adding to 31443221 its reverse (12234413), we get a palindrome (43677634).

The spelling of 31443221 in words is "thirty-one million, four hundred forty-three thousand, two hundred twenty-one".