31133621 has 2 divisors, whose sum is σ = 31133622. Its totient is φ = 31133620.

The previous prime is 31133593. The next prime is 31133639. The reversal of 31133621 is 12633113.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22193521 + 8940100 = 4711^2 + 2990^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31133621 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 31133593 and 31133602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31133671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15566810 + 15566811.

It is an arithmetic number, because the mean of its divisors is an integer number (15566811).

Almost surely, 2^31133621 is an apocalyptic number.

It is an amenable number.

31133621 is a deficient number, since it is larger than the sum of its proper divisors (1).

31133621 is an equidigital number, since it uses as much as digits as its factorization.

31133621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 324, while the sum is 20.

The square root of 31133621 is about 5579.7509801065. The cubic root of 31133621 is about 314.5887671395.

Adding to 31133621 its reverse (12633113), we get a palindrome (43766734).

The spelling of 31133621 in words is "thirty-one million, one hundred thirty-three thousand, six hundred twenty-one".