7821900440640 has 2688 divisors, whose sum is σ = 34891397222400. Its totient is φ = 1634876006400.

The previous prime is 7821900440597. The next prime is 7821900440671. The reversal of 7821900440640 is 460440091287.

7821900440640 is a `hidden beast` number, since 7 + 82 + 1 + 90 + 0 + 440 + 6 + 40 = 666.

It is a super-3 number, since 3×7821900440640³ (a number of 40 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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

It is a congruent number.

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 383 ways as a sum of consecutive naturals, for example, 110167611805 + ... + 110167611875.

Almost surely, 2^{7821900440640} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7821900440640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17445698611200).

7821900440640 is an abundant number, since it is smaller than the sum of its proper divisors (27069496781760).

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

7821900440640 is a wasteful number, since it uses less digits than its factorization.

7821900440640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191 (or 124 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The spelling of 7821900440640 in words is "seven trillion, eight hundred twenty-one billion, nine hundred million, four hundred forty thousand, six hundred forty".