75251221 has 2 divisors, whose sum is σ = 75251222. Its totient is φ = 75251220.

The previous prime is 75251219. The next prime is 75251233. The reversal of 75251221 is 12215257.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 69056100 + 6195121 = 8310^2 + 2489^2 .

It is an emirp because it is prime and its reverse (12215257) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 75251221 - 2¹ = 75251219 is a prime.

Together with 75251219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (75251261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 37625610 + 37625611.

It is an arithmetic number, because the mean of its divisors is an integer number (37625611).

Almost surely, 2^75251221 is an apocalyptic number.

It is an amenable number.

75251221 is a deficient number, since it is larger than the sum of its proper divisors (1).

75251221 is an equidigital number, since it uses as much as digits as its factorization.

75251221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1400, while the sum is 25.

The square root of 75251221 is about 8674.7461634333. The cubic root of 75251221 is about 422.1866701085.

Adding to 75251221 its reverse (12215257), we get a palindrome (87466478).

The spelling of 75251221 in words is "seventy-five million, two hundred fifty-one thousand, two hundred twenty-one".