77665 has 12 divisors (see below), whose sum is σ = 108756. Its totient is φ = 53088.

The previous prime is 77659. The next prime is 77681. The reversal of 77665 is 56677.

77665 = T₃₀ + T₃₁ + ... + T₇₈.

It can be written as a sum of positive squares in 2 ways, for example, as 14161 + 63504 = 119^2 + 252^2 .

It is not a de Polignac number, because 77665 - 2⁹ = 77153 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 87 + ... + 403.

It is an arithmetic number, because the mean of its divisors is an integer number (9063).

2⁷⁷⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

77665 is a deficient number, since it is larger than the sum of its proper divisors (31091).

77665 is a wasteful number, since it uses less digits than its factorization.

77665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336 (or 329 counting only the distinct ones).

The product of its digits is 8820, while the sum is 31.

The square root of 77665 is about 278.6844093235. The cubic root of 77665 is about 42.6653306331.

It can be divided in two parts, 776 and 65, that added together give a square (841 = 29²).

The spelling of 77665 in words is "seventy-seven thousand, six hundred sixty-five".