81130073 has 2 divisors, whose sum is σ = 81130074. Its totient is φ = 81130072.

The previous prime is 81130043. The next prime is 81130079. The reversal of 81130073 is 37003118.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71961289 + 9168784 = 8483^2 + 3028^2 .

It is a cyclic number.

It is not a de Polignac number, because 81130073 - 2¹⁶ = 81064537 is a prime.

It is not a weakly prime, because it can be changed into another prime (81130079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40565036 + 40565037.

It is an arithmetic number, because the mean of its divisors is an integer number (40565037).

Almost surely, 2^81130073 is an apocalyptic number.

It is an amenable number.

81130073 is a deficient number, since it is larger than the sum of its proper divisors (1).

81130073 is an equidigital number, since it uses as much as digits as its factorization.

81130073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 81130073 is about 9007.2233790442. The cubic root of 81130073 is about 432.9063493645.

The spelling of 81130073 in words is "eighty-one million, one hundred thirty thousand, seventy-three".