1821861823 has 8 divisors (see below), whose sum is σ = 1838955888. Its totient is φ = 1804785024.

The previous prime is 1821861817. The next prime is 1821861827. The reversal of 1821861823 is 3281681281.

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

It is a cyclic number.

It is not a de Polignac number, because 1821861823 - 2⁵ = 1821861791 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821861827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 317740 + ... + 323422.

It is an arithmetic number, because the mean of its divisors is an integer number (229869486).

Almost surely, 2^1821861823 is an apocalyptic number.

1821861823 is a deficient number, since it is larger than the sum of its proper divisors (17094065).

1821861823 is a wasteful number, since it uses less digits than its factorization.

1821861823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8633.

The product of its digits is 36864, while the sum is 40.

The square root of 1821861823 is about 42683.2733397990. The cubic root of 1821861823 is about 1221.3453364286.

The spelling of 1821861823 in words is "one billion, eight hundred twenty-one million, eight hundred sixty-one thousand, eight hundred twenty-three".