51710221 has 2 divisors, whose sum is σ = 51710222. Its totient is φ = 51710220.

The previous prime is 51710213. The next prime is 51710227. The reversal of 51710221 is 12201715.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26409321 + 25300900 = 5139^2 + 5030^2 .

It is a cyclic number.

It is not a de Polignac number, because 51710221 - 2³ = 51710213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51710227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25855110 + 25855111.

It is an arithmetic number, because the mean of its divisors is an integer number (25855111).

Almost surely, 2^51710221 is an apocalyptic number.

It is an amenable number.

51710221 is a deficient number, since it is larger than the sum of its proper divisors (1).

51710221 is an equidigital number, since it uses as much as digits as its factorization.

51710221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 51710221 is about 7190.9819218240. The cubic root of 51710221 is about 372.5564882878.

Adding to 51710221 its reverse (12201715), we get a palindrome (63911936).

The spelling of 51710221 in words is "fifty-one million, seven hundred ten thousand, two hundred twenty-one".