811111111985 has 8 divisors (see below), whose sum is σ = 991698114600. Its totient is φ = 636645702784.

The previous prime is 811111111957. The next prime is 811111111991. The reversal of 811111111985 is 589111111118.

It can be written as a sum of positive squares in 4 ways, for example, as 102328972321 + 708782139664 = 319889^2 + 841892^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 811111111985 - 2¹⁰ = 811111110961 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1530398060 + ... + 1530398589.

It is an arithmetic number, because the mean of its divisors is an integer number (123962264325).

Almost surely, 2^811111111985 is an apocalyptic number.

It is an amenable number.

811111111985 is a deficient number, since it is larger than the sum of its proper divisors (180587002615).

811111111985 is a wasteful number, since it uses less digits than its factorization.

811111111985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3060796707.

The product of its digits is 2880, while the sum is 38.

The spelling of 811111111985 in words is "eight hundred eleven billion, one hundred eleven million, one hundred eleven thousand, nine hundred eighty-five".