20728571 has 2 divisors, whose sum is σ = 20728572. Its totient is φ = 20728570.

The previous prime is 20728549. The next prime is 20728577. The reversal of 20728571 is 17582702.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20728571 - 2¹⁴ = 20712187 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20728577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10364285 + 10364286.

It is an arithmetic number, because the mean of its divisors is an integer number (10364286).

Almost surely, 2^20728571 is an apocalyptic number.

20728571 is a deficient number, since it is larger than the sum of its proper divisors (1).

20728571 is an equidigital number, since it uses as much as digits as its factorization.

20728571 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7840, while the sum is 32.

The square root of 20728571 is about 4552.8640436543. The cubic root of 20728571 is about 274.6986053352.

The spelling of 20728571 in words is "twenty million, seven hundred twenty-eight thousand, five hundred seventy-one".