81047871 has 20 divisors (see below), whose sum is σ = 124348312. Its totient is φ = 52569648.

The previous prime is 81047867. The next prime is 81047927. The reversal of 81047871 is 17874018.

It is not a de Polignac number, because 81047871 - 2² = 81047867 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 (81047801) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 10525 + ... + 16518.

Almost surely, 2^81047871 is an apocalyptic number.

81047871 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81047871 is a deficient number, since it is larger than the sum of its proper divisors (43300441).

81047871 is a wasteful number, since it uses less digits than its factorization.

81047871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27092 (or 27083 counting only the distinct ones).

The product of its (nonzero) digits is 12544, while the sum is 36.

The square root of 81047871 is about 9002.6591071749. The cubic root of 81047871 is about 432.7600912557.

It can be divided in two parts, 81047 and 871, that added together give a palindrome (81918).

The spelling of 81047871 in words is "eighty-one million, forty-seven thousand, eight hundred seventy-one".