20806417 has 2 divisors, whose sum is σ = 20806418. Its totient is φ = 20806416.

The previous prime is 20806397. The next prime is 20806433. The reversal of 20806417 is 71460802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18113536 + 2692881 = 4256^2 + 1641^2 .

It is a cyclic number.

It is not a de Polignac number, because 20806417 - 2¹¹ = 20804369 is a prime.

It is not a weakly prime, because it can be changed into another prime (20806117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10403208 + 10403209.

It is an arithmetic number, because the mean of its divisors is an integer number (10403209).

Almost surely, 2^20806417 is an apocalyptic number.

It is an amenable number.

20806417 is a deficient number, since it is larger than the sum of its proper divisors (1).

20806417 is an equidigital number, since it uses as much as digits as its factorization.

20806417 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 20806417 is about 4561.4051563087. The cubic root of 20806417 is about 275.0420519714.

The spelling of 20806417 in words is "twenty million, eight hundred six thousand, four hundred seventeen".