64865640 has 256 divisors, whose sum is σ = 238878720. Its totient is φ = 13777920.

The previous prime is 64865627. The next prime is 64865641. The reversal of 64865640 is 4656846.

It is not an unprimeable number, because it can be changed into a prime (64865641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1223854 + ... + 1223906.

It is an arithmetic number, because the mean of its divisors is an integer number (933120).

Almost surely, 2^64865640 is an apocalyptic number.

64865640 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 64865640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119439360).

64865640 is an abundant number, since it is smaller than the sum of its proper divisors (174013080).

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

64865640 is a wasteful number, since it uses less digits than its factorization.

64865640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 39.

The square root of 64865640 is about 8053.9207843137. The cubic root of 64865640 is about 401.7953464386.

The spelling of 64865640 in words is "sixty-four million, eight hundred sixty-five thousand, six hundred forty".