66464640 has 192 divisors, whose sum is σ = 250614000. Its totient is φ = 16097280.

The previous prime is 66464639. The next prime is 66464677. The reversal of 66464640 is 4646466.

It is a happy number.

66464640 is a `hidden beast` number, since 6 + 6 + 4 + 6 + 4 + 640 = 666.

66464640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (192).

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 = 66464595 and 66464604.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 62836 + ... + 63884.

Almost surely, 2^66464640 is an apocalyptic number.

66464640 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 66464640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125307000).

66464640 is an abundant number, since it is smaller than the sum of its proper divisors (184149360).

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

66464640 is a wasteful number, since it uses less digits than its factorization.

66464640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1085 (or 1070 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The square root of 66464640 is about 8152.5848661636. The cubic root of 66464640 is about 405.0701296024.

It can be divided in two parts, 6 and 6464640, that added together give a palindrome (6464646).

The spelling of 66464640 in words is "sixty-six million, four hundred sixty-four thousand, six hundred forty".