1820081 has 4 divisors (see below), whose sum is σ = 1843200. Its totient is φ = 1796964.

The previous prime is 1820051. The next prime is 1820087. The reversal of 1820081 is 1800281.

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.

It is a cyclic number.

It is not a de Polignac number, because 1820081 - 2¹⁰ = 1819057 is a prime.

It is a super-2 number, since 2×1820081² = 6625389693122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1820087) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11441 + ... + 11598.

It is an arithmetic number, because the mean of its divisors is an integer number (460800).

2^1820081 is an apocalyptic number.

It is an amenable number.

1820081 is a deficient number, since it is larger than the sum of its proper divisors (23119).

1820081 is an equidigital number, since it uses as much as digits as its factorization.

1820081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23118.

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 1820081 is about 1349.1037765865. The cubic root of 1820081 is about 122.0947262163.

It can be divided in two parts, 18200 and 81, that added together give a palindrome (18281).

The spelling of 1820081 in words is "one million, eight hundred twenty thousand, eighty-one".