20317945 has 4 divisors (see below), whose sum is σ = 24381540. Its totient is φ = 16254352.

The previous prime is 20317943. The next prime is 20317949. The reversal of 20317945 is 54971302.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15776784 + 4541161 = 3972^2 + 2131^2 .

It is a cyclic number.

It is not a de Polignac number, because 20317945 - 2¹ = 20317943 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20317943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2031790 + ... + 2031799.

It is an arithmetic number, because the mean of its divisors is an integer number (6095385).

Almost surely, 2^20317945 is an apocalyptic number.

It is an amenable number.

20317945 is a deficient number, since it is larger than the sum of its proper divisors (4063595).

20317945 is an equidigital number, since it uses as much as digits as its factorization.

20317945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4063594.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 20317945 is about 4507.5431223672. The cubic root of 20317945 is about 272.8725986251.

The spelling of 20317945 in words is "twenty million, three hundred seventeen thousand, nine hundred forty-five".