1802820021 has 32 divisors (see below), whose sum is σ = 2498276352. Its totient is φ = 1155651840.

The previous prime is 1802820011. The next prime is 1802820023. The reversal of 1802820021 is 1200282081.

It is not a de Polignac number, because 1802820021 - 2⁶ = 1802819957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1802819973 and 1802820000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1802820023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3201886 + ... + 3202448.

It is an arithmetic number, because the mean of its divisors is an integer number (78071136).

Almost surely, 2^1802820021 is an apocalyptic number.

It is an amenable number.

1802820021 is a deficient number, since it is larger than the sum of its proper divisors (695456331).

1802820021 is a wasteful number, since it uses less digits than its factorization.

1802820021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 953.

The product of its (nonzero) digits is 512, while the sum is 24.

The square root of 1802820021 is about 42459.6281307314. The cubic root of 1802820021 is about 1217.0753245944.

The spelling of 1802820021 in words is "one billion, eight hundred two million, eight hundred twenty thousand, twenty-one".