81318929 has 8 divisors (see below), whose sum is σ = 84309120. Its totient is φ = 78341200.

The previous prime is 81318911. The next prime is 81318931. The reversal of 81318929 is 92981318.

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 81318929 - 2¹² = 81314833 is a prime.

It is a super-2 number, since 2×81318929² = 13225536427414082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81318959) 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 7 ways as a sum of consecutive naturals, for example, 11384 + ... + 17094.

It is an arithmetic number, because the mean of its divisors is an integer number (10538640).

Almost surely, 2^81318929 is an apocalyptic number.

It is an amenable number.

81318929 is a deficient number, since it is larger than the sum of its proper divisors (2990191).

81318929 is a wasteful number, since it uses less digits than its factorization.

81318929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6231.

The product of its digits is 31104, while the sum is 41.

The square root of 81318929 is about 9017.7008710646. The cubic root of 81318929 is about 433.2419980415.

The spelling of 81318929 in words is "eighty-one million, three hundred eighteen thousand, nine hundred twenty-nine".