811381 has 4 divisors (see below), whose sum is σ = 819072. Its totient is φ = 803692.

The previous prime is 811379. The next prime is 811387. The reversal of 811381 is 183118.

811381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 811381 - 2¹ = 811379 is a prime.

It is a super-2 number, since 2×811381² = 1316678254322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811387) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3685 + ... + 3898.

It is an arithmetic number, because the mean of its divisors is an integer number (204768).

2⁸¹¹³⁸¹ is an apocalyptic number.

It is an amenable number.

811381 is a deficient number, since it is larger than the sum of its proper divisors (7691).

811381 is a wasteful number, since it uses less digits than its factorization.

811381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7690.

The product of its digits is 192, while the sum is 22.

The square root of 811381 is about 900.7668954841. The cubic root of 811381 is about 93.2699214961.

Adding to 811381 its reverse (183118), we get a palindrome (994499).

The spelling of 811381 in words is "eight hundred eleven thousand, three hundred eighty-one".