20417321 has 4 divisors (see below), whose sum is σ = 20554500. Its totient is φ = 20280144.

The previous prime is 20417281. The next prime is 20417329. The reversal of 20417321 is 12371402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12371402 = 2 ⋅6185701.

It can be written as a sum of positive squares in 2 ways, for example, as 960400 + 19456921 = 980^2 + 4411^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20417321 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20417293 and 20417302.

It is not an unprimeable number, because it can be changed into a prime (20417329) 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, 68366 + ... + 68663.

It is an arithmetic number, because the mean of its divisors is an integer number (5138625).

Almost surely, 2^20417321 is an apocalyptic number.

It is an amenable number.

20417321 is a deficient number, since it is larger than the sum of its proper divisors (137179).

20417321 is a wasteful number, since it uses less digits than its factorization.

20417321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137178.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 20417321 is about 4518.5529763410. The cubic root of 20417321 is about 273.3167527453.

Adding to 20417321 its reverse (12371402), we get a palindrome (32788723).

The spelling of 20417321 in words is "twenty million, four hundred seventeen thousand, three hundred twenty-one".