20529221 has 2 divisors, whose sum is σ = 20529222. Its totient is φ = 20529220.

The previous prime is 20529211. The next prime is 20529259. The reversal of 20529221 is 12292502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11826721 + 8702500 = 3439^2 + 2950^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20529221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20529211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10264610 + 10264611.

It is an arithmetic number, because the mean of its divisors is an integer number (10264611).

Almost surely, 2^20529221 is an apocalyptic number.

It is an amenable number.

20529221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20529221 is an equidigital number, since it uses as much as digits as its factorization.

20529221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 20529221 is about 4530.9183395864. The cubic root of 20529221 is about 273.8151602913.

The spelling of 20529221 in words is "twenty million, five hundred twenty-nine thousand, two hundred twenty-one".