81129699 has 24 divisors (see below), whose sum is σ = 134440800. Its totient is φ = 46182528.

The previous prime is 81129679. The next prime is 81129703. The reversal of 81129699 is 99692118.

It is not a de Polignac number, because 81129699 - 2⁹ = 81129187 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81129679) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15127 + ... + 19775.

It is an arithmetic number, because the mean of its divisors is an integer number (5601700).

Almost surely, 2^81129699 is an apocalyptic number.

81129699 is a deficient number, since it is larger than the sum of its proper divisors (53311101).

81129699 is a wasteful number, since it uses less digits than its factorization.

81129699 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4939 (or 4936 counting only the distinct ones).

The product of its digits is 69984, while the sum is 45.

The square root of 81129699 is about 9007.2026179053. The cubic root of 81129699 is about 432.9056841479.

The spelling of 81129699 in words is "eighty-one million, one hundred twenty-nine thousand, six hundred ninety-nine".