20825621 has 2 divisors, whose sum is σ = 20825622. Its totient is φ = 20825620.

The previous prime is 20825617. The next prime is 20825633. The reversal of 20825621 is 12652802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16924996 + 3900625 = 4114^2 + 1975^2 .

It is a cyclic number.

It is not a de Polignac number, because 20825621 - 2² = 20825617 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20825611) 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 as a sum of consecutive naturals, namely, 10412810 + 10412811.

It is an arithmetic number, because the mean of its divisors is an integer number (10412811).

Almost surely, 2^20825621 is an apocalyptic number.

It is an amenable number.

20825621 is a deficient number, since it is larger than the sum of its proper divisors (1).

20825621 is an equidigital number, since it uses as much as digits as its factorization.

20825621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 20825621 is about 4563.5097238858. The cubic root of 20825621 is about 275.1266457991.

The spelling of 20825621 in words is "twenty million, eight hundred twenty-five thousand, six hundred twenty-one".