1820821273 has 4 divisors (see below), whose sum is σ = 1833041700. Its totient is φ = 1808600848.

The previous prime is 1820821267. The next prime is 1820821333. The reversal of 1820821273 is 3721280281.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 268697664 + 1552123609 = 16392^2 + 39397^2 .

It is a cyclic number.

It is not a de Polignac number, because 1820821273 - 2²⁹ = 1283950361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1820821073) 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, 6109990 + ... + 6110287.

It is an arithmetic number, because the mean of its divisors is an integer number (458260425).

Almost surely, 2^1820821273 is an apocalyptic number.

It is an amenable number.

1820821273 is a deficient number, since it is larger than the sum of its proper divisors (12220427).

1820821273 is a wasteful number, since it uses less digits than its factorization.

1820821273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12220426.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 1820821273 is about 42671.0823978019. The cubic root of 1820821273 is about 1221.1127697758.

The spelling of 1820821273 in words is "one billion, eight hundred twenty million, eight hundred twenty-one thousand, two hundred seventy-three".