811411781 has 2 divisors, whose sum is σ = 811411782. Its totient is φ = 811411780.

The previous prime is 811411747. The next prime is 811411787. The reversal of 811411781 is 187114118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 507781156 + 303630625 = 22534^2 + 17425^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-811411781 is a prime.

It is a super-2 number, since 2×811411781² = 1316778156691183922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (811411787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 405705890 + 405705891.

It is an arithmetic number, because the mean of its divisors is an integer number (405705891).

Almost surely, 2^811411781 is an apocalyptic number.

It is an amenable number.

811411781 is a deficient number, since it is larger than the sum of its proper divisors (1).

811411781 is an equidigital number, since it uses as much as digits as its factorization.

811411781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1792, while the sum is 32.

The square root of 811411781 is about 28485.2906076101. The cubic root of 811411781 is about 932.7110092771.

Adding to 811411781 its reverse (187114118), we get a palindrome (998525899).

The spelling of 811411781 in words is "eight hundred eleven million, four hundred eleven thousand, seven hundred eighty-one".