64106640 has 200 divisors, whose sum is σ = 240094008. Its totient is φ = 15759360.

The previous prime is 64106639. The next prime is 64106641. The reversal of 64106640 is 4660146.

64106640 is a `hidden beast` number, since 6 + 4 + 10 + 6 + 640 = 666.

It is an interprime number because it is at equal distance from previous prime (64106639) and next prime (64106641).

It can be written as a sum of positive squares in 4 ways, for example, as 3640464 + 60466176 = 1908^2 + 7776^2 .

It is a super-2 number, since 2×64106640² = 8219322584179200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64106641) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 83860 + ... + 84620.

Almost surely, 2^64106640 is an apocalyptic number.

64106640 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 64106640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120047004).

64106640 is an abundant number, since it is smaller than the sum of its proper divisors (175987368).

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

64106640 is a wasteful number, since it uses less digits than its factorization.

64106640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 799 (or 784 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 64106640 is about 8006.6622259216. The cubic root of 64106640 is about 400.2220433857. Note that the first 3 decimals are identical.

Adding to 64106640 its reverse (4660146), we get a palindrome (68766786).

It can be divided in two parts, 64106 and 640, that added together give a palindrome (64746).

The spelling of 64106640 in words is "sixty-four million, one hundred six thousand, six hundred forty".