20728847 has 2 divisors, whose sum is σ = 20728848. Its totient is φ = 20728846.

The previous prime is 20728817. The next prime is 20728859. The reversal of 20728847 is 74882702.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20728847 - 2⁶ = 20728783 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20728847.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20728817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10364423 + 10364424.

It is an arithmetic number, because the mean of its divisors is an integer number (10364424).

Almost surely, 2^20728847 is an apocalyptic number.

20728847 is a deficient number, since it is larger than the sum of its proper divisors (1).

20728847 is an equidigital number, since it uses as much as digits as its factorization.

20728847 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 50176, while the sum is 38.

The square root of 20728847 is about 4552.8943541444. The cubic root of 20728847 is about 274.6998245296.

The spelling of 20728847 in words is "twenty million, seven hundred twenty-eight thousand, eight hundred forty-seven".