51784208666 has 8 divisors (see below), whose sum is σ = 78078781524. Its totient is φ = 25757948160.

The previous prime is 51784208653. The next prime is 51784208681. The reversal of 51784208666 is 66680248715.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 50185408441 + 1598800225 = 224021^2 + 39985^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67077605 + ... + 67078376.

Almost surely, 2^51784208666 is an apocalyptic number.

51784208666 is a deficient number, since it is larger than the sum of its proper divisors (26294572858).

51784208666 is a wasteful number, since it uses less digits than its factorization.

51784208666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134156176.

The product of its (nonzero) digits is 3870720, while the sum is 53.

The spelling of 51784208666 in words is "fifty-one billion, seven hundred eighty-four million, two hundred eight thousand, six hundred sixty-six".