81628859 has 12 divisors (see below), whose sum is σ = 91248192. Its totient is φ = 72914400.

The previous prime is 81628837. The next prime is 81628861. The reversal of 81628859 is 95882618.

It is a de Polignac number, because none of the positive numbers 2^k-81628859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81628829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2552 + ... + 13029.

It is an arithmetic number, because the mean of its divisors is an integer number (7604016).

Almost surely, 2^81628859 is an apocalyptic number.

81628859 is a deficient number, since it is larger than the sum of its proper divisors (9619333).

81628859 is a wasteful number, since it uses less digits than its factorization.

81628859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15638 (or 15625 counting only the distinct ones).

The product of its digits is 276480, while the sum is 47.

The square root of 81628859 is about 9034.8690637994. The cubic root of 81628859 is about 433.7917038636.

The spelling of 81628859 in words is "eighty-one million, six hundred twenty-eight thousand, eight hundred fifty-nine".