20549521 has 2 divisors, whose sum is σ = 20549522. Its totient is φ = 20549520.

The previous prime is 20549513. The next prime is 20549527. The reversal of 20549521 is 12594502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18190225 + 2359296 = 4265^2 + 1536^2 .

It is a cyclic number.

It is not a de Polignac number, because 20549521 - 2³ = 20549513 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20549521.

It is not a weakly prime, because it can be changed into another prime (20549527) 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, 10274760 + 10274761.

It is an arithmetic number, because the mean of its divisors is an integer number (10274761).

Almost surely, 2^20549521 is an apocalyptic number.

It is an amenable number.

20549521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20549521 is an equidigital number, since it uses as much as digits as its factorization.

20549521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 20549521 is about 4533.1579500388. The cubic root of 20549521 is about 273.9053831763.

The spelling of 20549521 in words is "twenty million, five hundred forty-nine thousand, five hundred twenty-one".