51785816716618 has 4 divisors (see below), whose sum is σ = 77678725074930. Its totient is φ = 25892908358308.

The previous prime is 51785816716541. The next prime is 51785816716651. The reversal of 51785816716618 is 81661761858715.

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., 50000271361569 + 1785545355049 = 7071087^2 + 1336243^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12946454179153 + ... + 12946454179156.

Almost surely, 2^{51785816716618} is an apocalyptic number.

51785816716618 is a deficient number, since it is larger than the sum of its proper divisors (25892908358312).

51785816716618 is a wasteful number, since it uses less digits than its factorization.

51785816716618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25892908358311.

The product of its digits is 135475200, while the sum is 70.

The spelling of 51785816716618 in words is "fifty-one trillion, seven hundred eighty-five billion, eight hundred sixteen million, seven hundred sixteen thousand, six hundred eighteen".