9811381 has 2 divisors, whose sum is σ = 9811382. Its totient is φ = 9811380.

The previous prime is 9811379. The next prime is 9811393. The reversal of 9811381 is 1831189.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8468100 + 1343281 = 2910^2 + 1159^2 .

It is a cyclic number.

It is not a de Polignac number, because 9811381 - 2¹ = 9811379 is a prime.

It is a super-2 number, since 2×9811381² = 192526394254322, which contains 22 as substring.

Together with 9811379, it forms a pair of twin primes.

It is a Chen prime.

9811381 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9811481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4905690 + 4905691.

It is an arithmetic number, because the mean of its divisors is an integer number (4905691).

Almost surely, 2^9811381 is an apocalyptic number.

It is an amenable number.

9811381 is a deficient number, since it is larger than the sum of its proper divisors (1).

9811381 is an equidigital number, since it uses as much as digits as its factorization.

9811381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 31.

The square root of 9811381 is about 3132.3124045982. The cubic root of 9811381 is about 214.0803043887.

The spelling of 9811381 in words is "nine million, eight hundred eleven thousand, three hundred eighty-one".