77889665 has 24 divisors (see below), whose sum is σ = 115129512. Its totient is φ = 50265600.

The previous prime is 77889649. The next prime is 77889677. The reversal of 77889665 is 56698877.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 6385729 + 71503936 = 2527^2 + 8456^2 .

It is not a de Polignac number, because 77889665 - 2⁴ = 77889649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 77889665.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5186 + ... + 13515.

It is an arithmetic number, because the mean of its divisors is an integer number (4797063).

Almost surely, 2^77889665 is an apocalyptic number.

It is an amenable number.

77889665 is a deficient number, since it is larger than the sum of its proper divisors (37239847).

77889665 is a wasteful number, since it uses less digits than its factorization.

77889665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18737 (or 18730 counting only the distinct ones).

The product of its digits is 5080320, while the sum is 56.

The square root of 77889665 is about 8825.5121664411. The cubic root of 77889665 is about 427.0643099412.

The spelling of 77889665 in words is "seventy-seven million, eight hundred eighty-nine thousand, six hundred sixty-five".