51686191 has 2 divisors, whose sum is σ = 51686192. Its totient is φ = 51686190.

The previous prime is 51686189. The next prime is 51686197. The reversal of 51686191 is 19168615.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51686191 - 2¹ = 51686189 is a prime.

Together with 51686189, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 51686191.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51686197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25843095 + 25843096.

It is an arithmetic number, because the mean of its divisors is an integer number (25843096).

Almost surely, 2^51686191 is an apocalyptic number.

51686191 is a deficient number, since it is larger than the sum of its proper divisors (1).

51686191 is an equidigital number, since it uses as much as digits as its factorization.

51686191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 37.

The square root of 51686191 is about 7189.3108849180. The cubic root of 51686191 is about 372.4987697210.

The spelling of 51686191 in words is "fifty-one million, six hundred eighty-six thousand, one hundred ninety-one".