3981635651840 has 288 divisors, whose sum is σ = 11913501551616. Its totient is φ = 1238640353280.

The previous prime is 3981635651797. The next prime is 3981635651911. The reversal of 3981635651840 is 481565361893.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 3981635651840.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51508259 + ... + 51585501.

It is an arithmetic number, because the mean of its divisors is an integer number (41366324832).

Almost surely, 2^{3981635651840} 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 3981635651840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5956750775808).

3981635651840 is an abundant number, since it is smaller than the sum of its proper divisors (7931865899776).

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

3981635651840 is a wasteful number, since it uses less digits than its factorization.

3981635651840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77805 (or 77791 counting only the distinct ones).

The product of its (nonzero) digits is 18662400, while the sum is 59.

The spelling of 3981635651840 in words is "three trillion, nine hundred eighty-one billion, six hundred thirty-five million, six hundred fifty-one thousand, eight hundred forty".