65217840 has 80 divisors (see below), whose sum is σ = 202963200. Its totient is φ = 17323776.

The previous prime is 65217793. The next prime is 65217847. The reversal of 65217840 is 4871256.

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

It is not an unprimeable number, because it can be changed into a prime (65217847) 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, 105051 + ... + 105669.

It is an arithmetic number, because the mean of its divisors is an integer number (2537040).

Almost surely, 2^65217840 is an apocalyptic number.

65217840 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 65217840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101481600).

65217840 is an abundant number, since it is smaller than the sum of its proper divisors (137745360).

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

65217840 is a wasteful number, since it uses less digits than its factorization.

65217840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1074 (or 1068 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 33.

The square root of 65217840 is about 8075.7563113308. The cubic root of 65217840 is about 402.5212416294.

The spelling of 65217840 in words is "sixty-five million, two hundred seventeen thousand, eight hundred forty".