31712321 has 2 divisors, whose sum is σ = 31712322. Its totient is φ = 31712320.

The previous prime is 31712309. The next prime is 31712347. The reversal of 31712321 is 12321713.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16974400 + 14737921 = 4120^2 + 3839^2 .

It is an emirp because it is prime and its reverse (12321713) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31712321 - 2²² = 27518017 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 31712293 and 31712302.

It is not a weakly prime, because it can be changed into another prime (31712521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15856160 + 15856161.

It is an arithmetic number, because the mean of its divisors is an integer number (15856161).

Almost surely, 2^31712321 is an apocalyptic number.

It is an amenable number.

31712321 is a deficient number, since it is larger than the sum of its proper divisors (1).

31712321 is an equidigital number, since it uses as much as digits as its factorization.

31712321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 252, while the sum is 20.

The square root of 31712321 is about 5631.3693716538. The cubic root of 31712321 is about 316.5259660561.

The spelling of 31712321 in words is "thirty-one million, seven hundred twelve thousand, three hundred twenty-one".