31661233 has 4 divisors (see below), whose sum is σ = 32516980. Its totient is φ = 30805488.

The previous prime is 31661219. The next prime is 31661269. The reversal of 31661233 is 33216613.

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

It can be written as a sum of positive squares in 2 ways, for example, as 29778849 + 1882384 = 5457^2 + 1372^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31661233 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31661198 and 31661207.

It is not an unprimeable number, because it can be changed into a prime (31661213) 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 3 ways as a sum of consecutive naturals, for example, 427818 + ... + 427891.

It is an arithmetic number, because the mean of its divisors is an integer number (8129245).

Almost surely, 2^31661233 is an apocalyptic number.

It is an amenable number.

31661233 is a deficient number, since it is larger than the sum of its proper divisors (855747).

31661233 is an equidigital number, since it uses as much as digits as its factorization.

31661233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 855746.

The product of its digits is 1944, while the sum is 25.

The square root of 31661233 is about 5626.8315240462. The cubic root of 31661233 is about 316.3559020832.

Adding to 31661233 its reverse (33216613), we get a palindrome (64877846).

The spelling of 31661233 in words is "thirty-one million, six hundred sixty-one thousand, two hundred thirty-three".