65491441920 has 720 divisors, whose sum is σ = 252018209520. Its totient is φ = 16180051968.

The previous prime is 65491441919. The next prime is 65491441949. The reversal of 65491441920 is 2914419456.

65491441920 is a `hidden beast` number, since 6 + 549 + 14 + 4 + 1 + 92 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 4999055616 + 60492386304 = 70704^2 + 245952^2 .

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 128666626 + ... + 128667134.

It is an arithmetic number, because the mean of its divisors is an integer number (350025291).

Almost surely, 2^65491441920 is an apocalyptic number.

65491441920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65491441920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126009104760).

65491441920 is an abundant number, since it is smaller than the sum of its proper divisors (186526767600).

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

65491441920 is a wasteful number, since it uses less digits than its factorization.

65491441920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 632 (or 609 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The spelling of 65491441920 in words is "sixty-five billion, four hundred ninety-one million, four hundred forty-one thousand, nine hundred twenty".