811806918 has 64 divisors (see below), whose sum is σ = 1819238400. Its totient is φ = 239783040.

The previous prime is 811806917. The next prime is 811806937. The reversal of 811806918 is 819608118.

It is a super-2 number, since 2×811806918² = 1318060944225317448, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 811806918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811806911) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 431103 + ... + 432981.

It is an arithmetic number, because the mean of its divisors is an integer number (28425600).

Almost surely, 2^811806918 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 811806918, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (909619200).

811806918 is an abundant number, since it is smaller than the sum of its proper divisors (1007431482).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

811806918 is a wasteful number, since it uses less digits than its factorization.

811806918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2117.

The product of its (nonzero) digits is 27648, while the sum is 42.

The square root of 811806918 is about 28492.2255711975. The cubic root of 811806918 is about 932.8623869254.

The spelling of 811806918 in words is "eight hundred eleven million, eight hundred six thousand, nine hundred eighteen".