20402321 has 2 divisors, whose sum is σ = 20402322. Its totient is φ = 20402320.

The previous prime is 20402287. The next prime is 20402351. The reversal of 20402321 is 12320402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14737921 + 5664400 = 3839^2 + 2380^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20402321 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20402296 and 20402305.

It is not a weakly prime, because it can be changed into another prime (20402351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10201160 + 10201161.

It is an arithmetic number, because the mean of its divisors is an integer number (10201161).

Almost surely, 2^20402321 is an apocalyptic number.

It is an amenable number.

20402321 is a deficient number, since it is larger than the sum of its proper divisors (1).

20402321 is an equidigital number, since it uses as much as digits as its factorization.

20402321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 20402321 is about 4516.8928479653. The cubic root of 20402321 is about 273.2498037776.

Adding to 20402321 its reverse (12320402), we get a palindrome (32722723).

The spelling of 20402321 in words is "twenty million, four hundred two thousand, three hundred twenty-one".