81087113 has 4 divisors (see below), whose sum is σ = 81285780. Its totient is φ = 80888448.

The previous prime is 81087107. The next prime is 81087131. The reversal of 81087113 is 31178018.

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

It can be written as a sum of positive squares in 2 ways, for example, as 58553104 + 22534009 = 7652^2 + 4747^2 .

It is a cyclic number.

It is not a de Polignac number, because 81087113 - 2¹² = 81083017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81087133) 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, 98720 + ... + 99537.

It is an arithmetic number, because the mean of its divisors is an integer number (20321445).

Almost surely, 2^81087113 is an apocalyptic number.

It is an amenable number.

81087113 is a deficient number, since it is larger than the sum of its proper divisors (198667).

81087113 is a wasteful number, since it uses less digits than its factorization.

81087113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198666.

The product of its (nonzero) digits is 1344, while the sum is 29.

The square root of 81087113 is about 9004.8383105973. The cubic root of 81087113 is about 432.8299250102.

The spelling of 81087113 in words is "eighty-one million, eighty-seven thousand, one hundred thirteen".