20833821 has 8 divisors (see below), whose sum is σ = 30864960. Its totient is φ = 13889196.

The previous prime is 20833811. The next prime is 20833859. The reversal of 20833821 is 12833802.

It is not a de Polignac number, because 20833821 - 2⁷ = 20833693 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 771623 = 20833821 / (2 + 0 + 8 + 3 + 3 + 8 + 2 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20833811) 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, 385785 + ... + 385838.

It is an arithmetic number, because the mean of its divisors is an integer number (3858120).

Almost surely, 2^20833821 is an apocalyptic number.

It is an amenable number.

20833821 is a deficient number, since it is larger than the sum of its proper divisors (10031139).

20833821 is an equidigital number, since it uses as much as digits as its factorization.

20833821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 771632 (or 771626 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 20833821 is about 4564.4080667705. The cubic root of 20833821 is about 275.1627510443.

The spelling of 20833821 in words is "twenty million, eight hundred thirty-three thousand, eight hundred twenty-one".