51217123418 has 4 divisors (see below), whose sum is σ = 76825685130. Its totient is φ = 25608561708.

The previous prime is 51217123381. The next prime is 51217123471. The reversal of 51217123418 is 81432171215.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 47810883649 + 3406239769 = 218657^2 + 58363^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 12804280853 + ... + 12804280856.

Almost surely, 2^51217123418 is an apocalyptic number.

51217123418 is a deficient number, since it is larger than the sum of its proper divisors (25608561712).

51217123418 is a wasteful number, since it uses less digits than its factorization.

51217123418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25608561711.

The product of its digits is 13440, while the sum is 35.

The spelling of 51217123418 in words is "fifty-one billion, two hundred seventeen million, one hundred twenty-three thousand, four hundred eighteen".