664871639040 has 2304 divisors, whose sum is σ = 3005009280000. Its totient is φ = 140460687360.

The previous prime is 664871639039. The next prime is 664871639053. The reversal of 664871639040 is 40936178466.

664871639040 is a `hidden beast` number, since 66 + 487 + 1 + 63 + 9 + 0 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (2304).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 16216381420 + ... + 16216381460.

It is an arithmetic number, because the mean of its divisors is an integer number (1304257500).

Almost surely, 2^664871639040 is an apocalyptic number.

664871639040 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 664871639040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1502504640000).

664871639040 is an abundant number, since it is smaller than the sum of its proper divisors (2340137640960).

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

664871639040 is an equidigital number, since it uses as much as digits as its factorization.

664871639040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 5225472, while the sum is 54.

The spelling of 664871639040 in words is "six hundred sixty-four billion, eight hundred seventy-one million, six hundred thirty-nine thousand, forty".