1820811 has 8 divisors (see below), whose sum is σ = 2436304. Its totient is φ = 1209600.

The previous prime is 1820809. The next prime is 1820813. The reversal of 1820811 is 1180281.

It is an interprime number because it is at equal distance from previous prime (1820809) and next prime (1820813).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1820811 - 2¹ = 1820809 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (1820813) 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 7 ways as a sum of consecutive naturals, for example, 111 + ... + 1911.

It is an arithmetic number, because the mean of its divisors is an integer number (304538).

2^1820811 is an apocalyptic number.

1820811 is a deficient number, since it is larger than the sum of its proper divisors (615493).

1820811 is a wasteful number, since it uses less digits than its factorization.

1820811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2141.

The product of its (nonzero) digits is 128, while the sum is 21.

The square root of 1820811 is about 1349.3742994440. The cubic root of 1820811 is about 122.1110473282. Note that the first 3 decimals are identical.

The spelling of 1820811 in words is "one million, eight hundred twenty thousand, eight hundred eleven".