81017131 has 4 divisors (see below), whose sum is σ = 87249232. Its totient is φ = 74785032.

The previous prime is 81017119. The next prime is 81017171. The reversal of 81017131 is 13171018.

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 81017131 - 2⁵ = 81017099 is a prime.

It is a super-2 number, since 2×81017131² = 13127551030942322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81017171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3116031 + ... + 3116056.

It is an arithmetic number, because the mean of its divisors is an integer number (21812308).

Almost surely, 2^81017131 is an apocalyptic number.

81017131 is a deficient number, since it is larger than the sum of its proper divisors (6232101).

81017131 is a wasteful number, since it uses less digits than its factorization.

81017131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6232100.

The product of its (nonzero) digits is 168, while the sum is 22.

The square root of 81017131 is about 9000.9516719067. The cubic root of 81017131 is about 432.7053716302.

Adding to 81017131 its reverse (13171018), we get a palindrome (94188149).

The spelling of 81017131 in words is "eighty-one million, seventeen thousand, one hundred thirty-one".