664215679440 has 640 divisors, whose sum is σ = 2445740605440. Its totient is φ = 165386188800.

The previous prime is 664215679397. The next prime is 664215679441. The reversal of 664215679440 is 44976512466.

664215679440 is a `hidden beast` number, since 6 + 6 + 42 + 156 + 7 + 9 + 440 = 666.

664215679440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664215679441) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 314643985 + ... + 314646095.

It is an arithmetic number, because the mean of its divisors is an integer number (3821469696).

Almost surely, 2^664215679440 is an apocalyptic number.

664215679440 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 664215679440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1222870302720).

664215679440 is an abundant number, since it is smaller than the sum of its proper divisors (1781524926000).

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

664215679440 is a wasteful number, since it uses less digits than its factorization.

664215679440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2328 (or 2316 counting only the distinct ones).

The product of its (nonzero) digits is 8709120, while the sum is 54.

The spelling of 664215679440 in words is "six hundred sixty-four billion, two hundred fifteen million, six hundred seventy-nine thousand, four hundred forty".