81313129 has 16 divisors (see below), whose sum is σ = 86771520. Its totient is φ = 76063680.

The previous prime is 81313117. The next prime is 81313139. The reversal of 81313129 is 92131318.

It is a cyclic number.

It is not a de Polignac number, because 81313129 - 2¹⁵ = 81280361 is a prime.

It is a super-2 number, since 2×81313129² = 13223649895541282, which contains 22 as substring.

It is a pancake number, because a pancake can be divided into 81313129 parts by 12752 straight cuts.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81313097 and 81313106.

It is not an unprimeable number, because it can be changed into a prime (81313109) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 245494 + ... + 245824.

It is an arithmetic number, because the mean of its divisors is an integer number (5423220).

Almost surely, 2^81313129 is an apocalyptic number.

It is an amenable number.

81313129 is a deficient number, since it is larger than the sum of its proper divisors (5458391).

81313129 is a wasteful number, since it uses less digits than its factorization.

81313129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 600.

The product of its digits is 1296, while the sum is 28.

The square root of 81313129 is about 9017.3792755989. The cubic root of 81313129 is about 433.2316975971.

The spelling of 81313129 in words is "eighty-one million, three hundred thirteen thousand, one hundred twenty-nine".