81329099 has 4 divisors (see below), whose sum is σ = 81382440. Its totient is φ = 81275760.

The previous prime is 81329077. The next prime is 81329107. The reversal of 81329099 is 99092318.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81329099 - 2⁸ = 81328843 is a prime.

It is a super-2 number, since 2×81329099² = 13228844688303602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81329029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24314 + ... + 27455.

It is an arithmetic number, because the mean of its divisors is an integer number (20345610).

Almost surely, 2^81329099 is an apocalyptic number.

81329099 is a deficient number, since it is larger than the sum of its proper divisors (53341).

81329099 is a wasteful number, since it uses less digits than its factorization.

81329099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53340.

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 81329099 is about 9018.2647443951. The cubic root of 81329099 is about 433.2600581558.

The spelling of 81329099 in words is "eighty-one million, three hundred twenty-nine thousand, ninety-nine".