81130129 has 2 divisors, whose sum is σ = 81130130. Its totient is φ = 81130128.

The previous prime is 81130097. The next prime is 81130163. The reversal of 81130129 is 92103118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78357904 + 2772225 = 8852^2 + 1665^2 .

It is a cyclic number.

It is not a de Polignac number, because 81130129 - 2⁵ = 81130097 is a prime.

It is not a weakly prime, because it can be changed into another prime (81130199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40565064 + 40565065.

It is an arithmetic number, because the mean of its divisors is an integer number (40565065).

Almost surely, 2^81130129 is an apocalyptic number.

It is an amenable number.

81130129 is a deficient number, since it is larger than the sum of its proper divisors (1).

81130129 is an equidigital number, since it uses as much as digits as its factorization.

81130129 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 81130129 is about 9007.2264876598. The cubic root of 81130129 is about 432.9064489690.

The spelling of 81130129 in words is "eighty-one million, one hundred thirty thousand, one hundred twenty-nine".