81824785 has 8 divisors (see below), whose sum is σ = 112216896. Its totient is φ = 56108400.

The previous prime is 81824783. The next prime is 81824819. The reversal of 81824785 is 58742818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81824785 - 2¹ = 81824783 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81824783) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1168891 + ... + 1168960.

It is an arithmetic number, because the mean of its divisors is an integer number (14027112).

Almost surely, 2^81824785 is an apocalyptic number.

It is an amenable number.

81824785 is a deficient number, since it is larger than the sum of its proper divisors (30392111).

81824785 is a wasteful number, since it uses less digits than its factorization.

81824785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2337863.

The product of its digits is 143360, while the sum is 43.

The square root of 81824785 is about 9045.7053345773. The cubic root of 81824785 is about 434.1384895726.

The spelling of 81824785 in words is "eighty-one million, eight hundred twenty-four thousand, seven hundred eighty-five".