20728633 has 2 divisors, whose sum is σ = 20728634. Its totient is φ = 20728632.

The previous prime is 20728619. The next prime is 20728637. The reversal of 20728633 is 33682702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13155129 + 7573504 = 3627^2 + 2752^2 .

It is a cyclic number.

It is not a de Polignac number, because 20728633 - 2⁹ = 20728121 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20728595 and 20728604.

It is not a weakly prime, because it can be changed into another prime (20728637) 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, 10364316 + 10364317.

It is an arithmetic number, because the mean of its divisors is an integer number (10364317).

Almost surely, 2^20728633 is an apocalyptic number.

It is an amenable number.

20728633 is a deficient number, since it is larger than the sum of its proper divisors (1).

20728633 is an equidigital number, since it uses as much as digits as its factorization.

20728633 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 31.

The square root of 20728633 is about 4552.8708525501. The cubic root of 20728633 is about 274.6988792131.

The spelling of 20728633 in words is "twenty million, seven hundred twenty-eight thousand, six hundred thirty-three".