1811638445 has 16 divisors (see below), whose sum is σ = 2226509040. Its totient is φ = 1414692864.

The previous prime is 1811638379. The next prime is 1811638457. The reversal of 1811638445 is 5448361181.

It can be written as a sum of positive squares in 8 ways, for example, as 179720836 + 1631917609 = 13406^2 + 40397^2 .

It is a cyclic number.

It is not a de Polignac number, because 1811638445 - 2¹⁴ = 1811622061 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9821 + ... + 60989.

It is an arithmetic number, because the mean of its divisors is an integer number (139156815).

Almost surely, 2^1811638445 is an apocalyptic number.

It is an amenable number.

1811638445 is a deficient number, since it is larger than the sum of its proper divisors (414870595).

1811638445 is an equidigital number, since it uses as much as digits as its factorization.

1811638445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51344.

The product of its digits is 92160, while the sum is 41.

The square root of 1811638445 is about 42563.3462617779. The cubic root of 1811638445 is about 1219.0565233130.

The spelling of 1811638445 in words is "one billion, eight hundred eleven million, six hundred thirty-eight thousand, four hundred forty-five".