51378391 has 2 divisors, whose sum is σ = 51378392. Its totient is φ = 51378390.

The previous prime is 51378323. The next prime is 51378433. The reversal of 51378391 is 19387315.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51378391 - 2¹³ = 51370199 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51378391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51378491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25689195 + 25689196.

It is an arithmetic number, because the mean of its divisors is an integer number (25689196).

Almost surely, 2^51378391 is an apocalyptic number.

51378391 is a deficient number, since it is larger than the sum of its proper divisors (1).

51378391 is an equidigital number, since it uses as much as digits as its factorization.

51378391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 37.

The square root of 51378391 is about 7167.8721389266. The cubic root of 51378391 is about 371.7578659970.

The spelling of 51378391 in words is "fifty-one million, three hundred seventy-eight thousand, three hundred ninety-one".