51302221 has 2 divisors, whose sum is σ = 51302222. Its totient is φ = 51302220.

The previous prime is 51302203. The next prime is 51302231. The reversal of 51302221 is 12220315.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30096196 + 21206025 = 5486^2 + 4605^2 .

It is a cyclic number.

It is not a de Polignac number, because 51302221 - 2¹⁵ = 51269453 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 51302195 and 51302204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51302201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25651110 + 25651111.

It is an arithmetic number, because the mean of its divisors is an integer number (25651111).

Almost surely, 2^51302221 is an apocalyptic number.

It is an amenable number.

51302221 is a deficient number, since it is larger than the sum of its proper divisors (1).

51302221 is an equidigital number, since it uses as much as digits as its factorization.

51302221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 51302221 is about 7162.5568758649. The cubic root of 51302221 is about 371.5740610864.

Adding to 51302221 its reverse (12220315), we get a palindrome (63522536).

The spelling of 51302221 in words is "fifty-one million, three hundred two thousand, two hundred twenty-one".