3921816955680 has 1440 divisors, whose sum is σ = 16660959671664. Its totient is φ = 860536700928.

The previous prime is 3921816955657. The next prime is 3921816955711. The reversal of 3921816955680 is 865596181293.

3921816955680 is a `hidden beast` number, since 3 + 9 + 2 + 1 + 8 + 1 + 69 + 5 + 568 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 881968913424 + 3039848042256 = 939132^2 + 1743516^2 .

It is a tau number, because it is divible by the number of its divisors (1440).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 1033959864 + ... + 1033963656.

Almost surely, 2^{3921816955680} is an apocalyptic number.

3921816955680 is a gapful number since it is divisible by the number (30) 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 3921816955680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8330479835832).

3921816955680 is an abundant number, since it is smaller than the sum of its proper divisors (12739142715984).

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

3921816955680 is a wasteful number, since it uses less digits than its factorization.

3921816955680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3888 (or 3852 counting only the distinct ones).

The product of its (nonzero) digits is 27993600, while the sum is 63.

It can be divided in two parts, 392181 and 6955680, that added together give a triangular number (7347861 = T₃₈₃₃).

The spelling of 3921816955680 in words is "three trillion, nine hundred twenty-one billion, eight hundred sixteen million, nine hundred fifty-five thousand, six hundred eighty".