51436721849 has 2 divisors, whose sum is σ = 51436721850. Its totient is φ = 51436721848.

The previous prime is 51436721837. The next prime is 51436721873. The reversal of 51436721849 is 94812763415.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51423725824 + 12996025 = 226768^2 + 3605^2 .

It is a cyclic number.

It is not a de Polignac number, because 51436721849 - 2²⁰ = 51435673273 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 51436721797 and 51436721806.

It is not a weakly prime, because it can be changed into another prime (51436729849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25718360924 + 25718360925.

It is an arithmetic number, because the mean of its divisors is an integer number (25718360925).

Almost surely, 2^51436721849 is an apocalyptic number.

It is an amenable number.

51436721849 is a deficient number, since it is larger than the sum of its proper divisors (1).

51436721849 is an equidigital number, since it uses as much as digits as its factorization.

51436721849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1451520, while the sum is 50.

The spelling of 51436721849 in words is "fifty-one billion, four hundred thirty-six million, seven hundred twenty-one thousand, eight hundred forty-nine".