81338971 has 12 divisors (see below), whose sum is σ = 98734032. Its totient is φ = 66686928.

The previous prime is 81338963. The next prime is 81339001. The reversal of 81338971 is 17983318.

It is not a de Polignac number, because 81338971 - 2³ = 81338963 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81338911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34960 + ... + 37213.

It is an arithmetic number, because the mean of its divisors is an integer number (8227836).

Almost surely, 2^81338971 is an apocalyptic number.

81338971 is a deficient number, since it is larger than the sum of its proper divisors (17395061).

81338971 is a wasteful number, since it uses less digits than its factorization.

81338971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72210 (or 72203 counting only the distinct ones).

The product of its digits is 36288, while the sum is 40.

The square root of 81338971 is about 9018.8120614635. The cubic root of 81338971 is about 433.2775876350.

The spelling of 81338971 in words is "eighty-one million, three hundred thirty-eight thousand, nine hundred seventy-one".