1981863108 has 72 divisors (see below), whose sum is σ = 5191187456. Its totient is φ = 636854400.

The previous prime is 1981863097. The next prime is 1981863109. The reversal of 1981863108 is 8013681891.

1981863108 is a `hidden beast` number, since 1 + 9 + 8 + 1 + 8 + 631 + 0 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (1981863109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 299160 + ... + 305712.

Almost surely, 2^1981863108 is an apocalyptic number.

1981863108 is a gapful number since it is divisible by the number (18) 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 1981863108, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2595593728).

1981863108 is an abundant number, since it is smaller than the sum of its proper divisors (3209324348).

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

1981863108 is a wasteful number, since it uses less digits than its factorization.

1981863108 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6865 (or 6860 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 45.

The square root of 1981863108 is about 44518.1211193824. The cubic root of 1981863108 is about 1256.1009704552.

The spelling of 1981863108 in words is "one billion, nine hundred eighty-one million, eight hundred sixty-three thousand, one hundred eight".