81816061 has 2 divisors, whose sum is σ = 81816062. Its totient is φ = 81816060.

The previous prime is 81816043. The next prime is 81816079. The reversal of 81816061 is 16061818.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (81816043) and next prime (81816079).

It can be written as a sum of positive squares in only one way, i.e., 56715961 + 25100100 = 7531^2 + 5010^2 .

It is a cyclic number.

It is not a de Polignac number, because 81816061 - 2¹⁷ = 81684989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81816001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40908030 + 40908031.

It is an arithmetic number, because the mean of its divisors is an integer number (40908031).

Almost surely, 2^81816061 is an apocalyptic number.

It is an amenable number.

81816061 is a deficient number, since it is larger than the sum of its proper divisors (1).

81816061 is an equidigital number, since it uses as much as digits as its factorization.

81816061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 81816061 is about 9045.2231039372. The cubic root of 81816061 is about 434.1230600228.

Adding to 81816061 its reverse (16061818), we get a palindrome (97877879).

The spelling of 81816061 in words is "eighty-one million, eight hundred sixteen thousand, sixty-one".