1812286721 has 4 divisors (see below), whose sum is σ = 2071184832. Its totient is φ = 1553388612.

The previous prime is 1812286711. The next prime is 1812286727. The reversal of 1812286721 is 1276822181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1276822181 = 71 ⋅17983411.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1812286721 is a prime.

It is a super-2 number, since 2×1812286721² = 6568766318225863682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1812286727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129449045 + ... + 129449058.

It is an arithmetic number, because the mean of its divisors is an integer number (517796208).

Almost surely, 2^1812286721 is an apocalyptic number.

It is an amenable number.

1812286721 is a deficient number, since it is larger than the sum of its proper divisors (258898111).

1812286721 is an equidigital number, since it uses as much as digits as its factorization.

1812286721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258898110.

The product of its digits is 21504, while the sum is 38.

The square root of 1812286721 is about 42570.9610063010. The cubic root of 1812286721 is about 1219.2019148769.

The spelling of 1812286721 in words is "one billion, eight hundred twelve million, two hundred eighty-six thousand, seven hundred twenty-one".