51207221 has 8 divisors (see below), whose sum is σ = 56081760. Its totient is φ = 46466352.

The previous prime is 51207217. The next prime is 51207227. The reversal of 51207221 is 12270215.

51207221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51207221 - 2² = 51207217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51207193 and 51207202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51207227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32615 + ... + 34148.

It is an arithmetic number, because the mean of its divisors is an integer number (7010220).

Almost surely, 2^51207221 is an apocalyptic number.

It is an amenable number.

51207221 is a deficient number, since it is larger than the sum of its proper divisors (4874539).

51207221 is a wasteful number, since it uses less digits than its factorization.

51207221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66835.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 51207221 is about 7155.9220929242. The cubic root of 51207221 is about 371.3445625939.

Adding to 51207221 its reverse (12270215), we get a palindrome (63477436).

The spelling of 51207221 in words is "fifty-one million, two hundred seven thousand, two hundred twenty-one".