1811801000 has 64 divisors (see below), whose sum is σ = 4247577360. Its totient is φ = 723360000.

The previous prime is 1811800999. The next prime is 1811801009. The reversal of 1811801000 is 1081181.

It can be written as a sum of positive squares in 8 ways, for example, as 95687524 + 1716113476 = 9782^2 + 41426^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (1811801009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 659630 + ... + 662370.

Almost surely, 2^1811801000 is an apocalyptic number.

1811801000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1811801000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2123788680).

1811801000 is an abundant number, since it is smaller than the sum of its proper divisors (2435776360).

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

1811801000 is a wasteful number, since it uses less digits than its factorization.

1811801000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3423 (or 3409 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 20.

The square root of 1811801000 is about 42565.2557845010. The cubic root of 1811801000 is about 1219.0929834590.

Adding to 1811801000 its reverse (1081181), we get a palindrome (1812882181).

The spelling of 1811801000 in words is "one billion, eight hundred eleven million, eight hundred one thousand".