64839840 has 96 divisors (see below), whose sum is σ = 219977856. Its totient is φ = 15959040.

The previous prime is 64839833. The next prime is 64839847. The reversal of 64839840 is 4893846.

It is an interprime number because it is at equal distance from previous prime (64839833) and next prime (64839847).

It is a tau number, because it is divible by the number of its divisors (96).

It is a junction number, because it is equal to n+sod(n) for n = 64839792 and 64839801.

It is not an unprimeable number, because it can be changed into a prime (64839847) 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, 1045 + ... + 11435.

It is an arithmetic number, because the mean of its divisors is an integer number (2291436).

Almost surely, 2^64839840 is an apocalyptic number.

64839840 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 64839840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109988928).

64839840 is an abundant number, since it is smaller than the sum of its proper divisors (155138016).

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

64839840 is a wasteful number, since it uses less digits than its factorization.

64839840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10422 (or 10414 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 42.

The square root of 64839840 is about 8052.3189206588. The cubic root of 64839840 is about 401.7420686445.

The spelling of 64839840 in words is "sixty-four million, eight hundred thirty-nine thousand, eight hundred forty".