20490917 has 2 divisors, whose sum is σ = 20490918. Its totient is φ = 20490916.

The previous prime is 20490839. The next prime is 20490929. The reversal of 20490917 is 71909402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20484676 + 6241 = 4526^2 + 79^2 .

It is a cyclic number.

It is not a de Polignac number, because 20490917 - 2²⁰ = 19442341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20490947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10245458 + 10245459.

It is an arithmetic number, because the mean of its divisors is an integer number (10245459).

Almost surely, 2^20490917 is an apocalyptic number.

It is an amenable number.

20490917 is a deficient number, since it is larger than the sum of its proper divisors (1).

20490917 is an equidigital number, since it uses as much as digits as its factorization.

20490917 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 20490917 is about 4526.6894083867. The cubic root of 20490917 is about 273.6447569146.

The spelling of 20490917 in words is "twenty million, four hundred ninety thousand, nine hundred seventeen".