81144061 has 2 divisors, whose sum is σ = 81144062. Its totient is φ = 81144060.

The previous prime is 81144031. The next prime is 81144083. The reversal of 81144061 is 16044118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50552100 + 30591961 = 7110^2 + 5531^2 .

It is a cyclic number.

It is not a de Polignac number, because 81144061 - 2⁵ = 81144029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81144031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40572030 + 40572031.

It is an arithmetic number, because the mean of its divisors is an integer number (40572031).

Almost surely, 2^81144061 is an apocalyptic number.

81144061 is the 4029-th centered decagonal number.

It is an amenable number.

81144061 is a deficient number, since it is larger than the sum of its proper divisors (1).

81144061 is an equidigital number, since it uses as much as digits as its factorization.

81144061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 81144061 is about 9007.9998334813. Note that the first 3 decimals coincide. The cubic root of 81144061 is about 432.9312277103.

Adding to 81144061 its reverse (16044118), we get a palindrome (97188179).

The spelling of 81144061 in words is "eighty-one million, one hundred forty-four thousand, sixty-one".