51999999999999 has 16 divisors (see below), whose sum is σ = 69530130908160. Its totient is φ = 34568289289440.

The previous prime is 51999999999989. The next prime is 52000000000079. The reversal of 51999999999999 is 99999999999915.

It is a happy number.

It is not a de Polignac number, because 51999999999999 - 2⁵ = 51999999999967 is a prime.

It is a super-9 number, since 9×51999999999999⁹ (a number of 125 digits) contains 999999999 as substring.

51999999999999 is a modest number, since divided by 9999999 gives 5199999 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51999999999989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7060069 + ... + 12403409.

It is an arithmetic number, because the mean of its divisors is an integer number (4345633181760).

Almost surely, 2^{51999999999999} is an apocalyptic number.

51999999999999 is a deficient number, since it is larger than the sum of its proper divisors (17530130908161).

51999999999999 is a wasteful number, since it uses less digits than its factorization.

51999999999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5352550.

The product of its digits is 1412147682405, while the sum is 114.

The spelling of 51999999999999 in words is "fifty-one trillion, nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".