81982271 has 4 divisors (see below), whose sum is σ = 93694032. Its totient is φ = 70270512.

The previous prime is 81982267. The next prime is 81982273. The reversal of 81982271 is 17228918.

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 81982271 - 2² = 81982267 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 (81982273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5855870 + ... + 5855883.

It is an arithmetic number, because the mean of its divisors is an integer number (23423508).

Almost surely, 2^81982271 is an apocalyptic number.

81982271 is a deficient number, since it is larger than the sum of its proper divisors (11711761).

81982271 is a wasteful number, since it uses less digits than its factorization.

81982271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11711760.

The product of its digits is 16128, while the sum is 38.

The square root of 81982271 is about 9054.4061649564. The cubic root of 81982271 is about 434.4168360305.

The spelling of 81982271 in words is "eighty-one million, nine hundred eighty-two thousand, two hundred seventy-one".