51840917861 has 2 divisors, whose sum is σ = 51840917862. Its totient is φ = 51840917860.

The previous prime is 51840917833. The next prime is 51840917867. The reversal of 51840917861 is 16871904815.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51838637761 + 2280100 = 227681^2 + 1510^2 .

It is a cyclic number.

It is not a de Polignac number, because 51840917861 - 2²⁶ = 51773808997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51840917867) 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, 25920458930 + 25920458931.

It is an arithmetic number, because the mean of its divisors is an integer number (25920458931).

Almost surely, 2^51840917861 is an apocalyptic number.

It is an amenable number.

51840917861 is a deficient number, since it is larger than the sum of its proper divisors (1).

51840917861 is an equidigital number, since it uses as much as digits as its factorization.

51840917861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 483840, while the sum is 50.

The spelling of 51840917861 in words is "fifty-one billion, eight hundred forty million, nine hundred seventeen thousand, eight hundred sixty-one".