64443840 has 56 divisors (see below), whose sum is σ = 204612240. Its totient is φ = 17184768.

The previous prime is 64443817. The next prime is 64443851. The reversal of 64443840 is 4834446.

It is a congruent number.

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, 32605 + ... + 34524.

It is an arithmetic number, because the mean of its divisors is an integer number (3653790).

Almost surely, 2^64443840 is an apocalyptic number.

64443840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

64443840 is an abundant number, since it is smaller than the sum of its proper divisors (140168400).

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

64443840 is a wasteful number, since it uses less digits than its factorization.

64443840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67149 (or 67139 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 33.

The square root of 64443840 is about 8027.6920718224. The cubic root of 64443840 is about 400.9225373431.

The spelling of 64443840 in words is "sixty-four million, four hundred forty-three thousand, eight hundred forty".