81113761 has 2 divisors, whose sum is σ = 81113762. Its totient is φ = 81113760.

The previous prime is 81113723. The next prime is 81113771. The reversal of 81113761 is 16731118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78411025 + 2702736 = 8855^2 + 1644^2 .

It is a cyclic number.

It is not a de Polignac number, because 81113761 - 2¹³ = 81105569 is a prime.

It is equal to p_4730761 and since 81113761 and 4730761 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (81113771) 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, 40556880 + 40556881.

It is an arithmetic number, because the mean of its divisors is an integer number (40556881).

Almost surely, 2^81113761 is an apocalyptic number.

It is an amenable number.

81113761 is a deficient number, since it is larger than the sum of its proper divisors (1).

81113761 is an equidigital number, since it uses as much as digits as its factorization.

81113761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 28.

The square root of 81113761 is about 9006.3178380512. The cubic root of 81113761 is about 432.8773340585.

Adding to 81113761 its reverse (16731118), we get a palindrome (97844879).

The spelling of 81113761 in words is "eighty-one million, one hundred thirteen thousand, seven hundred sixty-one".