1816831685 has 4 divisors (see below), whose sum is σ = 2180198028. Its totient is φ = 1453465344.

The previous prime is 1816831673. The next prime is 1816831691. The reversal of 1816831685 is 5861386181.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5861386181 = 7 ⋅837340883.

It can be written as a sum of positive squares in 2 ways, for example, as 667757281 + 1149074404 = 25841^2 + 33898^2 .

It is a cyclic number.

It is not a de Polignac number, because 1816831685 - 2¹² = 1816827589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 181683164 + ... + 181683173.

It is an arithmetic number, because the mean of its divisors is an integer number (545049507).

Almost surely, 2^1816831685 is an apocalyptic number.

It is an amenable number.

1816831685 is a deficient number, since it is larger than the sum of its proper divisors (363366343).

1816831685 is an equidigital number, since it uses as much as digits as its factorization.

1816831685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363366342.

The product of its digits is 276480, while the sum is 47.

The square root of 1816831685 is about 42624.3086160937. The cubic root of 1816831685 is about 1220.2202605539.

The spelling of 1816831685 in words is "one billion, eight hundred sixteen million, eight hundred thirty-one thousand, six hundred eighty-five".