65581311280 has 80 divisors (see below), whose sum is σ = 160651146240. Its totient is φ = 24848296704.

The previous prime is 65581311251. The next prime is 65581311343. The reversal of 65581311280 is 8211318556.

It is a happy number.

65581311280 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16501 + ... + 362539.

It is an arithmetic number, because the mean of its divisors is an integer number (2008139328).

Almost surely, 2^65581311280 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 65581311280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80325573120).

65581311280 is an abundant number, since it is smaller than the sum of its proper divisors (95069834960).

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

65581311280 is a wasteful number, since it uses less digits than its factorization.

65581311280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346178 (or 346172 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 40.

The spelling of 65581311280 in words is "sixty-five billion, five hundred eighty-one million, three hundred eleven thousand, two hundred eighty".