1981331368 has 32 divisors (see below), whose sum is σ = 3969642600. Its totient is φ = 923830272.

The previous prime is 1981331357. The next prime is 1981331369. The reversal of 1981331368 is 8631331891.

It can be written as a sum of positive squares in 4 ways, for example, as 1480556484 + 500774884 = 38478^2 + 22378^2 .

It is a super-3 number, since 3×1981331368³ (a number of 29 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (1981331369) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52005 + ... + 81652.

Almost surely, 2^1981331368 is an apocalyptic number.

It is an amenable number.

1981331368 is an abundant number, since it is smaller than the sum of its proper divisors (1988311232).

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

1981331368 is a wasteful number, since it uses less digits than its factorization.

1981331368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133789 (or 133785 counting only the distinct ones).

The product of its digits is 93312, while the sum is 43.

The square root of 1981331368 is about 44512.1485439649. The cubic root of 1981331368 is about 1255.9886218153.

The spelling of 1981331368 in words is "one billion, nine hundred eighty-one million, three hundred thirty-one thousand, three hundred sixty-eight".