81947411 has 16 divisors (see below), whose sum is σ = 102144000. Its totient is φ = 64011168.

The previous prime is 81947389. The next prime is 81947423. The reversal of 81947411 is 11474918.

It is not a de Polignac number, because 81947411 - 2¹⁸ = 81685267 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81947431) 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 15 ways as a sum of consecutive naturals, for example, 1490 + ... + 12888.

It is an arithmetic number, because the mean of its divisors is an integer number (6384000).

Almost surely, 2^81947411 is an apocalyptic number.

81947411 is a deficient number, since it is larger than the sum of its proper divisors (20196589).

81947411 is a wasteful number, since it uses less digits than its factorization.

81947411 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11498.

The product of its digits is 8064, while the sum is 35.

The square root of 81947411 is about 9052.4809306620. The cubic root of 81947411 is about 434.3552539443.

The spelling of 81947411 in words is "eighty-one million, nine hundred forty-seven thousand, four hundred eleven".