20844521 has 2 divisors, whose sum is σ = 20844522. Its totient is φ = 20844520.

The previous prime is 20844517. The next prime is 20844553. The reversal of 20844521 is 12544802.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13980121 + 6864400 = 3739^2 + 2620^2 .

It is a cyclic number.

It is not a de Polignac number, because 20844521 - 2² = 20844517 is a prime.

It is not a weakly prime, because it can be changed into another prime (20844721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10422260 + 10422261.

It is an arithmetic number, because the mean of its divisors is an integer number (10422261).

Almost surely, 2^20844521 is an apocalyptic number.

It is an amenable number.

20844521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20844521 is an equidigital number, since it uses as much as digits as its factorization.

20844521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2560, while the sum is 26.

The square root of 20844521 is about 4565.5800288682. The cubic root of 20844521 is about 275.2098497424.

The spelling of 20844521 in words is "twenty million, eight hundred forty-four thousand, five hundred twenty-one".