51557321 has 2 divisors, whose sum is σ = 51557322. Its totient is φ = 51557320.

The previous prime is 51557299. The next prime is 51557351. The reversal of 51557321 is 12375515.

It is a happy number.

51557321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29278921 + 22278400 = 5411^2 + 4720^2 .

It is a cyclic number.

It is not a de Polignac number, because 51557321 - 2⁶ = 51557257 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (51557351) 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 as a sum of consecutive naturals, namely, 25778660 + 25778661.

It is an arithmetic number, because the mean of its divisors is an integer number (25778661).

Almost surely, 2^51557321 is an apocalyptic number.

It is an amenable number.

51557321 is a deficient number, since it is larger than the sum of its proper divisors (1).

51557321 is an equidigital number, since it uses as much as digits as its factorization.

51557321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5250, while the sum is 29.

The square root of 51557321 is about 7180.3426798447. The cubic root of 51557321 is about 372.1889263684.

The spelling of 51557321 in words is "fifty-one million, five hundred fifty-seven thousand, three hundred twenty-one".