81871135 has 4 divisors (see below), whose sum is σ = 98245368. Its totient is φ = 65496904.

The previous prime is 81871129. The next prime is 81871169. The reversal of 81871135 is 53117818.

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 81871135 - 2⁵ = 81871103 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81871135.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8187109 + ... + 8187118.

It is an arithmetic number, because the mean of its divisors is an integer number (24561342).

Almost surely, 2^81871135 is an apocalyptic number.

81871135 is a deficient number, since it is larger than the sum of its proper divisors (16374233).

81871135 is a wasteful number, since it uses less digits than its factorization.

81871135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16374232.

The product of its digits is 6720, while the sum is 34.

The square root of 81871135 is about 9048.2669611368. The cubic root of 81871135 is about 434.2204473019.

The spelling of 81871135 in words is "eighty-one million, eight hundred seventy-one thousand, one hundred thirty-five".