20844257 has 6 divisors (see below), whose sum is σ = 24247458. Its totient is φ = 17866464.

The previous prime is 20844253. The next prime is 20844259. The reversal of 20844257 is 75244802.

It can be written as a sum of positive squares in only one way, i.e., 20830096 + 14161 = 4564^2 + 119^2 .

It is not a de Polignac number, because 20844257 - 2² = 20844253 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20844253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 212648 + ... + 212745.

It is an arithmetic number, because the mean of its divisors is an integer number (4041243).

Almost surely, 2^20844257 is an apocalyptic number.

It is an amenable number.

20844257 is a deficient number, since it is larger than the sum of its proper divisors (3403201).

20844257 is an equidigital number, since it uses as much as digits as its factorization.

20844257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425407 (or 425400 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 32.

The square root of 20844257 is about 4565.5511167875. The cubic root of 20844257 is about 275.2086878750.

The spelling of 20844257 in words is "twenty million, eight hundred forty-four thousand, two hundred fifty-seven".