1811938897 has 4 divisors (see below), whose sum is σ = 1918523556. Its totient is φ = 1705354240.

The previous prime is 1811938837. The next prime is 1811938901. The reversal of 1811938897 is 7988391181.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 731107521 + 1080831376 = 27039^2 + 32876^2 .

It is a cyclic number.

It is not a de Polignac number, because 1811938897 - 2²³ = 1803550289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1811938837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53292304 + ... + 53292337.

It is an arithmetic number, because the mean of its divisors is an integer number (479630889).

Almost surely, 2^1811938897 is an apocalyptic number.

1811938897 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1811938897 is a deficient number, since it is larger than the sum of its proper divisors (106584659).

1811938897 is a wasteful number, since it uses less digits than its factorization.

1811938897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106584658.

The product of its digits is 870912, while the sum is 55.

The square root of 1811938897 is about 42566.8755841910. The cubic root of 1811938897 is about 1219.1239112486.

The spelling of 1811938897 in words is "one billion, eight hundred eleven million, nine hundred thirty-eight thousand, eight hundred ninety-seven".