1978986898791 has 48 divisors (see below), whose sum is σ = 3301299555840. Its totient is φ = 1118955729600.

The previous prime is 1978986898787. The next prime is 1978986898807.

It is a happy number.

1978986898791 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1978986898791 - 2² = 1978986898787 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1978986898711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 10205646 + ... + 10397748.

It is an arithmetic number, because the mean of its divisors is an integer number (68777074080).

Almost surely, 2^{1978986898791} is an apocalyptic number.

1978986898791 is a deficient number, since it is larger than the sum of its proper divisors (1322312657049).

1978986898791 is a wasteful number, since it uses less digits than its factorization.

1978986898791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193836 (or 193833 counting only the distinct ones).

The product of its digits is 7900913664, while the sum is 90.

The spelling of 1978986898791 in words is "one trillion, nine hundred seventy-eight billion, nine hundred eighty-six million, eight hundred ninety-eight thousand, seven hundred ninety-one".