51681988219 has 2 divisors, whose sum is σ = 51681988220. Its totient is φ = 51681988218.

The previous prime is 51681988199. The next prime is 51681988261. The reversal of 51681988219 is 91288918615.

51681988219 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51681988219 - 2⁷ = 51681988091 is a prime.

It is a super-2 number, since 2×51681988219² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (51681988289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25840994109 + 25840994110.

It is an arithmetic number, because the mean of its divisors is an integer number (25840994110).

Almost surely, 2^51681988219 is an apocalyptic number.

51681988219 is a deficient number, since it is larger than the sum of its proper divisors (1).

51681988219 is an equidigital number, since it uses as much as digits as its factorization.

51681988219 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2488320, while the sum is 58.

The spelling of 51681988219 in words is "fifty-one billion, six hundred eighty-one million, nine hundred eighty-eight thousand, two hundred nineteen".