81971141 has 4 divisors (see below), whose sum is σ = 93681312. Its totient is φ = 70260972.

The previous prime is 81971137. The next prime is 81971147. The reversal of 81971141 is 14117918.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81971141 - 2² = 81971137 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81971098 and 81971107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81971147) 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, 5855075 + ... + 5855088.

It is an arithmetic number, because the mean of its divisors is an integer number (23420328).

Almost surely, 2^81971141 is an apocalyptic number.

It is an amenable number.

81971141 is a deficient number, since it is larger than the sum of its proper divisors (11710171).

81971141 is a wasteful number, since it uses less digits than its factorization.

81971141 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11710170.

The product of its digits is 2016, while the sum is 32.

The square root of 81971141 is about 9053.7915262060. The cubic root of 81971141 is about 434.3971761775.

The spelling of 81971141 in words is "eighty-one million, nine hundred seventy-one thousand, one hundred forty-one".