1816081 has 4 divisors (see below), whose sum is σ = 1834164. Its totient is φ = 1798000.

The previous prime is 1816069. The next prime is 1816091. The reversal of 1816081 is 1806181.

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: 1806181 = 13 ⋅138937.

It can be written as a sum of positive squares in 2 ways, for example, as 1782225 + 33856 = 1335^2 + 184^2 .

It is a cyclic number.

It is not a de Polignac number, because 1816081 - 2¹⁹ = 1291793 is a prime.

It is a super-2 number, since 2×1816081² = 6596300397122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1816051) 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, 8890 + ... + 9091.

It is an arithmetic number, because the mean of its divisors is an integer number (458541).

2^1816081 is an apocalyptic number.

It is an amenable number.

1816081 is a deficient number, since it is larger than the sum of its proper divisors (18083).

1816081 is a wasteful number, since it uses less digits than its factorization.

1816081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18082.

The product of its (nonzero) digits is 384, while the sum is 25.

The square root of 1816081 is about 1347.6204955402. The cubic root of 1816081 is about 122.0052179082.

The spelling of 1816081 in words is "one million, eight hundred sixteen thousand, eighty-one".