664007991840 has 288 divisors, whose sum is σ = 2347050940416. Its totient is φ = 170768701440.

The previous prime is 664007991839. The next prime is 664007991901. The reversal of 664007991840 is 48199700466.

664007991840 is a `hidden beast` number, since 6 + 6 + 400 + 79 + 91 + 84 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×664007991840² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 13054137 + ... + 13104903.

It is an arithmetic number, because the mean of its divisors is an integer number (8149482432).

Almost surely, 2^664007991840 is an apocalyptic number.

664007991840 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 664007991840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1173525470208).

664007991840 is an abundant number, since it is smaller than the sum of its proper divisors (1683042948576).

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

664007991840 is a wasteful number, since it uses less digits than its factorization.

664007991840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51112 (or 51101 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 54.

The spelling of 664007991840 in words is "six hundred sixty-four billion, seven million, nine hundred ninety-one thousand, eight hundred forty".