81871373 has 4 divisors (see below), whose sum is σ = 81895548. Its totient is φ = 81847200.

The previous prime is 81871357. The next prime is 81871397. The reversal of 81871373 is 37317818.

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 17197609 + 64673764 = 4147^2 + 8042^2 .

It is a cyclic number.

It is not a de Polignac number, because 81871373 - 2⁴ = 81871357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81871313) 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, 5978 + ... + 14123.

It is an arithmetic number, because the mean of its divisors is an integer number (20473887).

Almost surely, 2^81871373 is an apocalyptic number.

It is an amenable number.

81871373 is a deficient number, since it is larger than the sum of its proper divisors (24175).

81871373 is a wasteful number, since it uses less digits than its factorization.

81871373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24174.

The product of its digits is 28224, while the sum is 38.

The square root of 81871373 is about 9048.2801128170. The cubic root of 81871373 is about 434.2208680622.

The spelling of 81871373 in words is "eighty-one million, eight hundred seventy-one thousand, three hundred seventy-three".