81128429 has 8 divisors (see below), whose sum is σ = 84770880. Its totient is φ = 77495616.

The previous prime is 81128419. The next prime is 81128473. The reversal of 81128429 is 92482118.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81128429 - 2⁴ = 81128413 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81128419) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18917 + ... + 22805.

It is an arithmetic number, because the mean of its divisors is an integer number (10596360).

Almost surely, 2^81128429 is an apocalyptic number.

It is an amenable number.

81128429 is a deficient number, since it is larger than the sum of its proper divisors (3642451).

81128429 is a wasteful number, since it uses less digits than its factorization.

81128429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4819.

The product of its digits is 9216, while the sum is 35.

The square root of 81128429 is about 9007.1321184937. The cubic root of 81128429 is about 432.9034252419.

The spelling of 81128429 in words is "eighty-one million, one hundred twenty-eight thousand, four hundred twenty-nine".