64855440 has 240 divisors, whose sum is σ = 241703280. Its totient is φ = 15575040.

The previous prime is 64855403. The next prime is 64855477. The reversal of 64855440 is 4455846.

64855440 is a `hidden beast` number, since 64 + 8 + 554 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (64855403) and next prime (64855477).

It can be written as a sum of positive squares in 8 ways, for example, as 61214976 + 3640464 = 7824^2 + 1908^2 .

It is a tau number, because it is divible by the number of its divisors (240).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 64855395 and 64855404.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1581820 + ... + 1581860.

It is an arithmetic number, because the mean of its divisors is an integer number (1007097).

Almost surely, 2^64855440 is an apocalyptic number.

64855440 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 64855440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120851640).

64855440 is an abundant number, since it is smaller than the sum of its proper divisors (176847840).

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

64855440 is a wasteful number, since it uses less digits than its factorization.

64855440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99 (or 64 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 36.

The square root of 64855440 is about 8053.2875274636. The cubic root of 64855440 is about 401.7742848135.

The spelling of 64855440 in words is "sixty-four million, eight hundred fifty-five thousand, four hundred forty".