77781587055769 has 27 divisors (see below), whose sum is σ = 80137373835133. Its totient is φ = 75493952720000.

The previous prime is 77781587055761. The next prime is 77781587055817. The reversal of 77781587055769 is 96755078518777.

It is a happy number.

The square root of 77781587055769 is 8819387.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 216788016025 + 77564799039744 = 465605^2 + 8807088^2 .

It is not a de Polignac number, because 77781587055769 - 2³ = 77781587055761 is a prime.

It is a super-2 number, since 2×77781587055769² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 77781587055692 and 77781587055701.

It is not an unprimeable number, because it can be changed into a prime (77781587055761) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 90760311189 + ... + 90760312045.

Almost surely, 2^{77781587055769} is an apocalyptic number.

77781587055769 is the 8819387-th square number.

77781587055769 is the 4409694-th centered octagonal number.

It is an amenable number.

77781587055769 is a deficient number, since it is larger than the sum of its proper divisors (2355786779364).

77781587055769 is an frugal number, since it uses more digits than its factorization.

77781587055769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2298 (or 1149 counting only the distinct ones).

The product of its (nonzero) digits is 7260624000, while the sum is 82.

The spelling of 77781587055769 in words is "seventy-seven trillion, seven hundred eighty-one billion, five hundred eighty-seven million, fifty-five thousand, seven hundred sixty-nine".