311605321 has 2 divisors, whose sum is σ = 311605322. Its totient is φ = 311605320.

The previous prime is 311605313. The next prime is 311605331. The reversal of 311605321 is 123506113.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 279558400 + 32046921 = 16720^2 + 5661^2 .

It is a cyclic number.

It is not a de Polignac number, because 311605321 - 2³ = 311605313 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 311605292 and 311605301.

It is not a weakly prime, because it can be changed into another prime (311605331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155802660 + 155802661.

It is an arithmetic number, because the mean of its divisors is an integer number (155802661).

Almost surely, 2^311605321 is an apocalyptic number.

It is an amenable number.

311605321 is a deficient number, since it is larger than the sum of its proper divisors (1).

311605321 is an equidigital number, since it uses as much as digits as its factorization.

311605321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 311605321 is about 17652.3460480470. The cubic root of 311605321 is about 677.9561764849.

It can be divided in two parts, 31160 and 5321, that added together give a square (36481 = 191²).

The spelling of 311605321 in words is "three hundred eleven million, six hundred five thousand, three hundred twenty-one".