81445129 has 4 divisors (see below), whose sum is σ = 82476160. Its totient is φ = 80414100.

The previous prime is 81445123. The next prime is 81445141. The reversal of 81445129 is 92154418.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81445129 - 2³ = 81445121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81445094 and 81445103.

It is not an unprimeable number, because it can be changed into a prime (81445121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 515397 + ... + 515554.

It is an arithmetic number, because the mean of its divisors is an integer number (20619040).

Almost surely, 2^81445129 is an apocalyptic number.

It is an amenable number.

81445129 is a deficient number, since it is larger than the sum of its proper divisors (1031031).

81445129 is a wasteful number, since it uses less digits than its factorization.

81445129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1031030.

The product of its digits is 11520, while the sum is 34.

The square root of 81445129 is about 9024.6955073288. The cubic root of 81445129 is about 433.4660003391.

The spelling of 81445129 in words is "eighty-one million, four hundred forty-five thousand, one hundred twenty-nine".