65780 has 48 divisors (see below), whose sum is σ = 169344. Its totient is φ = 21120.

The previous prime is 65777. The next prime is 65789. The reversal of 65780 is 8756.

65780 is a nontrivial binomial coefficient, being equal to C(26, 5).

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65789) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2849 + ... + 2871.

It is an arithmetic number, because the mean of its divisors is an integer number (3528).

2⁶⁵⁷⁸⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84672).

65780 is an abundant number, since it is smaller than the sum of its proper divisors (103564).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

65780 is a wasteful number, since it uses less digits than its factorization.

65780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56 (or 54 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 65780 is about 256.4761197461. The cubic root of 65780 is about 40.3674475549.

It can be divided in two parts, 657 and 80, that added together give a palindrome (737).

The spelling of 65780 in words is "sixty-five thousand, seven hundred eighty".