20563651 has 2 divisors, whose sum is σ = 20563652. Its totient is φ = 20563650.

The previous prime is 20563637. The next prime is 20563657. The reversal of 20563651 is 15636502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20563651 - 2⁹ = 20563139 is a prime.

It is not a weakly prime, because it can be changed into another prime (20563657) 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, 10281825 + 10281826.

It is an arithmetic number, because the mean of its divisors is an integer number (10281826).

Almost surely, 2^20563651 is an apocalyptic number.

20563651 is a deficient number, since it is larger than the sum of its proper divisors (1).

20563651 is an equidigital number, since it uses as much as digits as its factorization.

20563651 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 20563651 is about 4534.7161983965. The cubic root of 20563651 is about 273.9681485699.

The spelling of 20563651 in words is "twenty million, five hundred sixty-three thousand, six hundred fifty-one".