20855017 has 2 divisors, whose sum is σ = 20855018. Its totient is φ = 20855016.

The previous prime is 20854991. The next prime is 20855041. The reversal of 20855017 is 71055802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18455616 + 2399401 = 4296^2 + 1549^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20855017 is a prime.

It is not a weakly prime, because it can be changed into another prime (20855057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10427508 + 10427509.

It is an arithmetic number, because the mean of its divisors is an integer number (10427509).

Almost surely, 2^20855017 is an apocalyptic number.

It is an amenable number.

20855017 is a deficient number, since it is larger than the sum of its proper divisors (1).

20855017 is an equidigital number, since it uses as much as digits as its factorization.

20855017 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2800, while the sum is 28.

The square root of 20855017 is about 4566.7293548009. The cubic root of 20855017 is about 275.2560348267.

It can be divided in two parts, 208 and 55017, that added together give a square (55225 = 235²).

The spelling of 20855017 in words is "twenty million, eight hundred fifty-five thousand, seventeen".