664043520 has 256 divisors, whose sum is σ = 2441047680. Its totient is φ = 150994944.

The previous prime is 664043459. The next prime is 664043531. The reversal of 664043520 is 25340466.

664043520 is digitally balanced in base 6, 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 (256).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3440544 + ... + 3440736.

Almost surely, 2^664043520 is an apocalyptic number.

664043520 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 664043520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1220523840).

664043520 is an abundant number, since it is smaller than the sum of its proper divisors (1777004160).

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

664043520 is an equidigital number, since it uses as much as digits as its factorization.

664043520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238 (or 210 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 30.

The square root of 664043520 is about 25769.0418913859. The cubic root of 664043520 is about 872.4331938460.

Adding to 664043520 its reverse (25340466), we get a palindrome (689383986).

The spelling of 664043520 in words is "six hundred sixty-four million, forty-three thousand, five hundred twenty".