1981523968 has 144 divisors (see below), whose sum is σ = 4347907200. Its totient is φ = 901570560.

The previous prime is 1981523959. The next prime is 1981523969. The reversal of 1981523968 is 8693251891.

It is not an unprimeable number, because it can be changed into a prime (1981523969) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33585123 + ... + 33585181.

It is an arithmetic number, because the mean of its divisors is an integer number (30193800).

Almost surely, 2^1981523968 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 1981523968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2173953600).

1981523968 is an abundant number, since it is smaller than the sum of its proper divisors (2366383232).

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

1981523968 is an equidigital number, since it uses as much as digits as its factorization.

1981523968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158 (or 115 counting only the distinct ones).

The product of its digits is 933120, while the sum is 52.

The square root of 1981523968 is about 44514.3119457102. The cubic root of 1981523968 is about 1256.0293176112.

The spelling of 1981523968 in words is "one billion, nine hundred eighty-one million, five hundred twenty-three thousand, nine hundred sixty-eight".