664644133440 has 336 divisors, whose sum is σ = 2614626094080. Its totient is φ = 151805767680.

The previous prime is 664644133411. The next prime is 664644133453. The reversal of 664644133440 is 44331446466.

It is a tau number, because it is divible by the number of its divisors (336).

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 28797105 + ... + 28820175.

It is an arithmetic number, because the mean of its divisors is an integer number (7781625280).

Almost surely, 2^664644133440 is an apocalyptic number.

664644133440 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 664644133440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1307313047040).

664644133440 is an abundant number, since it is smaller than the sum of its proper divisors (1949981960640).

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

664644133440 is a wasteful number, since it uses less digits than its factorization.

664644133440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24530 (or 24517 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 45.

The spelling of 664644133440 in words is "six hundred sixty-four billion, six hundred forty-four million, one hundred thirty-three thousand, four hundred forty".