51981191 has 2 divisors, whose sum is σ = 51981192. Its totient is φ = 51981190.

The previous prime is 51981151. The next prime is 51981197. The reversal of 51981191 is 19118915.

51981191 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 51981191 - 2¹⁴ = 51964807 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51981197) 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, 25990595 + 25990596.

It is an arithmetic number, because the mean of its divisors is an integer number (25990596).

Almost surely, 2^51981191 is an apocalyptic number.

51981191 is a deficient number, since it is larger than the sum of its proper divisors (1).

51981191 is an equidigital number, since it uses as much as digits as its factorization.

51981191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 35.

The square root of 51981191 is about 7209.7982634745. The cubic root of 51981191 is about 373.2061071762.

The spelling of 51981191 in words is "fifty-one million, nine hundred eighty-one thousand, one hundred ninety-one".