65491440 has 120 divisors (see below), whose sum is σ = 236212560. Its totient is φ = 14966784.

The previous prime is 65491421. The next prime is 65491441. The reversal of 65491440 is 4419456.

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65491441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8976 + ... + 14544.

It is an arithmetic number, because the mean of its divisors is an integer number (1968438).

Almost surely, 2^65491440 is an apocalyptic number.

65491440 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 65491440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118106280).

65491440 is an abundant number, since it is smaller than the sum of its proper divisors (170721120).

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

65491440 is a wasteful number, since it uses less digits than its factorization.

65491440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5599 (or 5586 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

The square root of 65491440 is about 8092.6781722740. The cubic root of 65491440 is about 403.0833381619.

The spelling of 65491440 in words is "sixty-five million, four hundred ninety-one thousand, four hundred forty".