20672321 has 2 divisors, whose sum is σ = 20672322. Its totient is φ = 20672320.

The previous prime is 20672299. The next prime is 20672371. The reversal of 20672321 is 12327602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11999296 + 8673025 = 3464^2 + 2945^2 .

It is a cyclic number.

It is not a de Polignac number, because 20672321 - 2²² = 16478017 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20672371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10336160 + 10336161.

It is an arithmetic number, because the mean of its divisors is an integer number (10336161).

Almost surely, 2^20672321 is an apocalyptic number.

It is an amenable number.

20672321 is a deficient number, since it is larger than the sum of its proper divisors (1).

20672321 is an equidigital number, since it uses as much as digits as its factorization.

20672321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 20672321 is about 4546.6824168838. The cubic root of 20672321 is about 274.4499019946.

Adding to 20672321 its reverse (12327602), we get a palindrome (32999923).

It can be divided in two parts, 206 and 72321, that added together give a palindrome (72527).

The spelling of 20672321 in words is "twenty million, six hundred seventy-two thousand, three hundred twenty-one".