51785198677 has 4 divisors (see below), whose sum is σ = 51840466636. Its totient is φ = 51729930720.

The previous prime is 51785198653. The next prime is 51785198683. The reversal of 51785198677 is 77689158715.

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

It can be written as a sum of positive squares in 2 ways, for example, as 25988341681 + 25796856996 = 161209^2 + 160614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51785198677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51785198477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27632574 + ... + 27634447.

It is an arithmetic number, because the mean of its divisors is an integer number (12960116659).

Almost surely, 2^51785198677 is an apocalyptic number.

It is an amenable number.

51785198677 is a deficient number, since it is larger than the sum of its proper divisors (55267959).

51785198677 is an equidigital number, since it uses as much as digits as its factorization.

51785198677 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55267958.

The product of its digits is 29635200, while the sum is 64.

The spelling of 51785198677 in words is "fifty-one billion, seven hundred eighty-five million, one hundred ninety-eight thousand, six hundred seventy-seven".