1812861 has 10 divisors (see below), whose sum is σ = 2708222. Its totient is φ = 1208520.

The previous prime is 1812851. The next prime is 1812869. The reversal of 1812861 is 1682181.

It can be written as a sum of positive squares in only one way, i.e., 1610361 + 202500 = 1269^2 + 450^2 .

It is not a de Polignac number, because 1812861 - 2¹⁰ = 1811837 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1812869) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 11110 + ... + 11271.

2^1812861 is an apocalyptic number.

It is an amenable number.

1812861 is a deficient number, since it is larger than the sum of its proper divisors (895361).

1812861 is an equidigital number, since it uses as much as digits as its factorization.

1812861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22393 (or 22384 counting only the distinct ones).

The product of its digits is 768, while the sum is 27.

The square root of 1812861 is about 1346.4252671426. The cubic root of 1812861 is about 121.9330681866.

The spelling of 1812861 in words is "one million, eight hundred twelve thousand, eight hundred sixty-one".