81116831 has 4 divisors (see below), whose sum is σ = 81259464. Its totient is φ = 80974200.

The previous prime is 81116803. The next prime is 81116851. The reversal of 81116831 is 13861118.

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 81116831 - 2¹⁴ = 81100447 is a prime.

It is a super-2 number, since 2×81116831² = 13159880542965122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81116794 and 81116803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81116851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70460 + ... + 71601.

It is an arithmetic number, because the mean of its divisors is an integer number (20314866).

Almost surely, 2^81116831 is an apocalyptic number.

81116831 is a deficient number, since it is larger than the sum of its proper divisors (142633).

81116831 is a wasteful number, since it uses less digits than its factorization.

81116831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142632.

The product of its digits is 1152, while the sum is 29.

The square root of 81116831 is about 9006.4882723512. The cubic root of 81116831 is about 432.8827951814.

Adding to 81116831 its reverse (13861118), we get a palindrome (94977949).

The spelling of 81116831 in words is "eighty-one million, one hundred sixteen thousand, eight hundred thirty-one".