51311663649 has 20 divisors (see below), whose sum is σ = 76663073520. Its totient is φ = 34202279160.

The previous prime is 51311663521. The next prime is 51311663671. The reversal of 51311663649 is 94636611315.

51311663649 is a `hidden beast` number, since 5 + 1 + 3 + 1 + 1 + 6 + 636 + 4 + 9 = 666.

It is not a de Polignac number, because 51311663649 - 2⁷ = 51311663521 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51311683649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 491814 + ... + 586944.

It is an arithmetic number, because the mean of its divisors is an integer number (3833153676).

Almost surely, 2^51311663649 is an apocalyptic number.

It is an amenable number.

51311663649 is a deficient number, since it is larger than the sum of its proper divisors (25351409871).

51311663649 is an equidigital number, since it uses as much as digits as its factorization.

51311663649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101802 (or 101793 counting only the distinct ones).

The product of its digits is 349920, while the sum is 45.

The spelling of 51311663649 in words is "fifty-one billion, three hundred eleven million, six hundred sixty-three thousand, six hundred forty-nine".