311605381 has 2 divisors, whose sum is σ = 311605382. Its totient is φ = 311605380.

The previous prime is 311605369. The next prime is 311605417. The reversal of 311605381 is 183506113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162154756 + 149450625 = 12734^2 + 12225^2 .

It is a cyclic number.

It is not a de Polignac number, because 311605381 - 2¹⁷ = 311474309 is a prime.

It is a super-2 number, since 2×311605381² = 194195826936310322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (311605321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155802690 + 155802691.

It is an arithmetic number, because the mean of its divisors is an integer number (155802691).

Almost surely, 2^311605381 is an apocalyptic number.

It is an amenable number.

311605381 is a deficient number, since it is larger than the sum of its proper divisors (1).

311605381 is an equidigital number, since it uses as much as digits as its factorization.

311605381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 311605381 is about 17652.3477475377. The cubic root of 311605381 is about 677.9562199986.

The spelling of 311605381 in words is "three hundred eleven million, six hundred five thousand, three hundred eighty-one".