51111778877 has 4 divisors (see below), whose sum is σ = 51454811100. Its totient is φ = 50768746656.

The previous prime is 51111778871. The next prime is 51111778901. The reversal of 51111778877 is 77887711115.

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 12155283001 + 38956495876 = 110251^2 + 197374^2 .

It is a cyclic number.

It is not a de Polignac number, because 51111778877 - 2¹² = 51111774781 is a prime.

It is a super-2 number, since 2×51111778877² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51111778871) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 171515888 + ... + 171516185.

It is an arithmetic number, because the mean of its divisors is an integer number (12863702775).

Almost surely, 2^51111778877 is an apocalyptic number.

It is an amenable number.

51111778877 is a deficient number, since it is larger than the sum of its proper divisors (343032223).

51111778877 is a wasteful number, since it uses less digits than its factorization.

51111778877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343032222.

The product of its digits is 768320, while the sum is 53.

The spelling of 51111778877 in words is "fifty-one billion, one hundred eleven million, seven hundred seventy-eight thousand, eight hundred seventy-seven".