1981305608 has 8 divisors (see below), whose sum is σ = 3714948030. Its totient is φ = 990652800.

The previous prime is 1981305593. The next prime is 1981305619. The reversal of 1981305608 is 8065031891.

It can be written as a sum of positive squares in only one way, i.e., 1494750244 + 486555364 = 38662^2 + 22058^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-3 number, since 3×1981305608³ (a number of 29 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123831593 + ... + 123831608.

Almost surely, 2^1981305608 is an apocalyptic number.

It is an amenable number.

1981305608 is a deficient number, since it is larger than the sum of its proper divisors (1733642422).

1981305608 is a wasteful number, since it uses less digits than its factorization.

1981305608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247663207 (or 247663203 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 41.

The square root of 1981305608 is about 44511.8591838175. The cubic root of 1981305608 is about 1255.9831786055.

The spelling of 1981305608 in words is "one billion, nine hundred eighty-one million, three hundred five thousand, six hundred eight".