64243840 has 64 divisors (see below), whose sum is σ = 157791960. Its totient is φ = 24993792.

The previous prime is 64243819. The next prime is 64243859. The reversal of 64243840 is 4834246.

It can be written as a sum of positive squares in 4 ways, for example, as 63616576 + 627264 = 7976^2 + 792^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22324 + ... + 25036.

Almost surely, 2^64243840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64243840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78895980).

64243840 is an abundant number, since it is smaller than the sum of its proper divisors (93548120).

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

64243840 is a wasteful number, since it uses less digits than its factorization.

64243840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2769 (or 2757 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 31.

The square root of 64243840 is about 8015.2255114875. The cubic root of 64243840 is about 400.5073562021.

The spelling of 64243840 in words is "sixty-four million, two hundred forty-three thousand, eight hundred forty".