20406917 has 2 divisors, whose sum is σ = 20406918. Its totient is φ = 20406916.

The previous prime is 20406833. The next prime is 20406941. The reversal of 20406917 is 71960402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19483396 + 923521 = 4414^2 + 961^2 .

It is a cyclic number.

It is not a de Polignac number, because 20406917 - 2¹⁰ = 20405893 is a prime.

It is a super-2 number, since 2×20406917² = 832884522889778, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20406917.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20406017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10203458 + 10203459.

It is an arithmetic number, because the mean of its divisors is an integer number (10203459).

Almost surely, 2^20406917 is an apocalyptic number.

It is an amenable number.

20406917 is a deficient number, since it is larger than the sum of its proper divisors (1).

20406917 is an equidigital number, since it uses as much as digits as its factorization.

20406917 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 20406917 is about 4517.4015761276. The cubic root of 20406917 is about 273.2703204272.

The spelling of 20406917 in words is "twenty million, four hundred six thousand, nine hundred seventeen".