20416321 has 4 divisors (see below), whose sum is σ = 21074944. Its totient is φ = 19757700.

The previous prime is 20416313. The next prime is 20416339. The reversal of 20416321 is 12361402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20416321 - 2³ = 20416313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20416381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 329265 + ... + 329326.

It is an arithmetic number, because the mean of its divisors is an integer number (5268736).

Almost surely, 2^20416321 is an apocalyptic number.

It is an amenable number.

20416321 is a deficient number, since it is larger than the sum of its proper divisors (658623).

20416321 is an equidigital number, since it uses as much as digits as its factorization.

20416321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658622.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 20416321 is about 4518.4423200922. The cubic root of 20416321 is about 273.3122905011.

Adding to 20416321 its reverse (12361402), we get a palindrome (32777723).

The spelling of 20416321 in words is "twenty million, four hundred sixteen thousand, three hundred twenty-one".