51225221 has 4 divisors (see below), whose sum is σ = 51258444. Its totient is φ = 51192000.

The previous prime is 51225179. The next prime is 51225227. The reversal of 51225221 is 12252215.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 43744996 + 7480225 = 6614^2 + 2735^2 .

It is a cyclic number.

It is not a de Polignac number, because 51225221 - 2²² = 47030917 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51225193 and 51225202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51225227) 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 in 3 ways as a sum of consecutive naturals, for example, 14180 + ... + 17421.

It is an arithmetic number, because the mean of its divisors is an integer number (12814611).

Almost surely, 2^51225221 is an apocalyptic number.

It is an amenable number.

51225221 is a deficient number, since it is larger than the sum of its proper divisors (33223).

51225221 is a wasteful number, since it uses less digits than its factorization.

51225221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33222.

The product of its digits is 400, while the sum is 20.

The square root of 51225221 is about 7157.1796819697. The cubic root of 51225221 is about 371.3880683011.

Adding to 51225221 its reverse (12252215), we get a palindrome (63477436).

The spelling of 51225221 in words is "fifty-one million, two hundred twenty-five thousand, two hundred twenty-one".