20559551 has 2 divisors, whose sum is σ = 20559552. Its totient is φ = 20559550.

The previous prime is 20559529. The next prime is 20559557. The reversal of 20559551 is 15595502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20559551 - 2¹⁴ = 20543167 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20559557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10279775 + 10279776.

It is an arithmetic number, because the mean of its divisors is an integer number (10279776).

Almost surely, 2^20559551 is an apocalyptic number.

20559551 is a deficient number, since it is larger than the sum of its proper divisors (1).

20559551 is an equidigital number, since it uses as much as digits as its factorization.

20559551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11250, while the sum is 32.

The square root of 20559551 is about 4534.2641078790. The cubic root of 20559551 is about 273.9499393510.

The spelling of 20559551 in words is "twenty million, five hundred fifty-nine thousand, five hundred fifty-one".