77764572769 has 27 divisors (see below), whose sum is σ = 88950581433. Its totient is φ = 67944412224.

The previous prime is 77764572757. The next prime is 77764572779. The reversal of 77764572769 is 96727546777.

The square root of 77764572769 is 278863.

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 46218550225 + 31546022544 = 214985^2 + 177612^2 .

It is not a de Polignac number, because 77764572769 - 2²³ = 77756184161 is a prime.

It is a super-2 number, since 2×77764572769² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77764572779) 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, 68878597 + ... + 68879725.

It is an arithmetic number, because the mean of its divisors is an integer number (3294465979).

Almost surely, 2^77764572769 is an apocalyptic number.

77764572769 is the 278863-rd square number.

77764572769 is the 139432-nd centered octagonal number.

It is an amenable number.

77764572769 is a deficient number, since it is larger than the sum of its proper divisors (11186008664).

77764572769 is an equidigital number, since it uses as much as digits as its factorization.

77764572769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2322 (or 1161 counting only the distinct ones).

The product of its digits is 217818720, while the sum is 67.

The spelling of 77764572769 in words is "seventy-seven billion, seven hundred sixty-four million, five hundred seventy-two thousand, seven hundred sixty-nine".