813121 has 2 divisors, whose sum is σ = 813122. Its totient is φ = 813120.

The previous prime is 813107. The next prime is 813133. The reversal of 813121 is 121318.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 680625 + 132496 = 825^2 + 364^2 .

It is a cyclic number.

It is not a de Polignac number, because 813121 - 2⁵ = 813089 is a prime.

It is a super-2 number, since 2×813121² = 1322331521282, which contains 22 as substring.

813121 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 813095 and 813104.

It is not a weakly prime, because it can be changed into another prime (813221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406560 + 406561.

It is an arithmetic number, because the mean of its divisors is an integer number (406561).

2⁸¹³¹²¹ is an apocalyptic number.

It is an amenable number.

813121 is a deficient number, since it is larger than the sum of its proper divisors (1).

813121 is an equidigital number, since it uses as much as digits as its factorization.

813121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48, while the sum is 16.

The square root of 813121 is about 901.7322218930. The cubic root of 813121 is about 93.3365460912.

Adding to 813121 its reverse (121318), we get a palindrome (934439).

The spelling of 813121 in words is "eight hundred thirteen thousand, one hundred twenty-one".