81478089 has 32 divisors (see below), whose sum is σ = 150497280. Its totient is φ = 42325200.

The previous prime is 81478087. The next prime is 81478129. The reversal of 81478089 is 98087418.

81478089 = T₂₂₇ + T₂₂₈ + ... + T₇₉₃.

It is not a de Polignac number, because 81478089 - 2¹ = 81478087 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81478087) 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 31 ways as a sum of consecutive naturals, for example, 17517 + ... + 21674.

It is an arithmetic number, because the mean of its divisors is an integer number (4703040).

Almost surely, 2^81478089 is an apocalyptic number.

It is an amenable number.

81478089 is a deficient number, since it is larger than the sum of its proper divisors (69019191).

81478089 is a wasteful number, since it uses less digits than its factorization.

81478089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39218 (or 39212 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The square root of 81478089 is about 9026.5214230068. The cubic root of 81478089 is about 433.5244655197.

The spelling of 81478089 in words is "eighty-one million, four hundred seventy-eight thousand, eighty-nine".