81384471 has 12 divisors (see below), whose sum is σ = 134349072. Its totient is φ = 46505376.

The previous prime is 81384463. The next prime is 81384481. The reversal of 81384471 is 17448318.

It is not a de Polignac number, because 81384471 - 2³ = 81384463 is a prime.

It is a super-3 number, since 3×81384471³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81384421) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 645846 + ... + 645971.

It is an arithmetic number, because the mean of its divisors is an integer number (11195756).

Almost surely, 2^81384471 is an apocalyptic number.

81384471 is a deficient number, since it is larger than the sum of its proper divisors (52964601).

81384471 is a wasteful number, since it uses less digits than its factorization.

81384471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1291830 (or 1291827 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 81384471 is about 9021.3342139619. The cubic root of 81384471 is about 433.3583625911.

The spelling of 81384471 in words is "eighty-one million, three hundred eighty-four thousand, four hundred seventy-one".