51251321 has 4 divisors (see below), whose sum is σ = 55910544. Its totient is φ = 46592100.

The previous prime is 51251287. The next prime is 51251359. The reversal of 51251321 is 12315215.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51251321 - 2¹⁸ = 50989177 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 51251293 and 51251302.

It is not an unprimeable number, because it can be changed into a prime (51250321) 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, 2329595 + ... + 2329616.

It is an arithmetic number, because the mean of its divisors is an integer number (13977636).

Almost surely, 2^51251321 is an apocalyptic number.

It is an amenable number.

51251321 is a deficient number, since it is larger than the sum of its proper divisors (4659223).

51251321 is a wasteful number, since it uses less digits than its factorization.

51251321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4659222.

The product of its digits is 300, while the sum is 20.

The square root of 51251321 is about 7159.0027936857. The cubic root of 51251321 is about 371.4511334773.

Adding to 51251321 its reverse (12315215), we get a palindrome (63566536).

It can be divided in two parts, 5125 and 1321, that added together give a palindrome (6446).

The spelling of 51251321 in words is "fifty-one million, two hundred fifty-one thousand, three hundred twenty-one".