20317691 has 2 divisors, whose sum is σ = 20317692. Its totient is φ = 20317690.

The previous prime is 20317681. The next prime is 20317711. The reversal of 20317691 is 19671302.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20317691 - 2¹⁸ = 20055547 is a prime.

It is not a weakly prime, because it can be changed into another prime (20317651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10158845 + 10158846.

It is an arithmetic number, because the mean of its divisors is an integer number (10158846).

Almost surely, 2^20317691 is an apocalyptic number.

20317691 is a deficient number, since it is larger than the sum of its proper divisors (1).

20317691 is an equidigital number, since it uses as much as digits as its factorization.

20317691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 20317691 is about 4507.5149472853. The cubic root of 20317691 is about 272.8714615362.

Adding to 20317691 its reverse (19671302), we get a palindrome (39988993).

The spelling of 20317691 in words is "twenty million, three hundred seventeen thousand, six hundred ninety-one".