51550391 has 2 divisors, whose sum is σ = 51550392. Its totient is φ = 51550390.

The previous prime is 51550381. The next prime is 51550393. The reversal of 51550391 is 19305515.

It is a happy number.

51550391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51550391 - 2¹⁸ = 51288247 is a prime.

Together with 51550393, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51550393) 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, 25775195 + 25775196.

It is an arithmetic number, because the mean of its divisors is an integer number (25775196).

Almost surely, 2^51550391 is an apocalyptic number.

51550391 is a deficient number, since it is larger than the sum of its proper divisors (1).

51550391 is an equidigital number, since it uses as much as digits as its factorization.

51550391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3375, while the sum is 29.

The square root of 51550391 is about 7179.8600961300. The cubic root of 51550391 is about 372.1722498823.

The spelling of 51550391 in words is "fifty-one million, five hundred fifty thousand, three hundred ninety-one".