65985840 has 200 divisors, whose sum is σ = 243064800. Its totient is φ = 16533504.

The previous prime is 65985839. The next prime is 65985847. The reversal of 65985840 is 4858956.

65985840 is a `hidden beast` number, since 6 + 598 + 58 + 4 + 0 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65985847) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 109861 + ... + 110459.

It is an arithmetic number, because the mean of its divisors is an integer number (1215324).

Almost surely, 2^65985840 is an apocalyptic number.

65985840 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 65985840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121532400).

65985840 is an abundant number, since it is smaller than the sum of its proper divisors (177078960).

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

65985840 is a wasteful number, since it uses less digits than its factorization.

65985840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 641 (or 626 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The square root of 65985840 is about 8123.1668701314. The cubic root of 65985840 is about 404.0950990059.

The spelling of 65985840 in words is "sixty-five million, nine hundred eighty-five thousand, eight hundred forty".