1981917312 has 32 divisors (see below), whose sum is σ = 5264468880. Its totient is φ = 660638976.

The previous prime is 1981917293. The next prime is 1981917313. The reversal of 1981917312 is 2137191891.

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (1981917313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2580238 + ... + 2581005.

Almost surely, 2^1981917312 is an apocalyptic number.

1981917312 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1981917312 is an abundant number, since it is smaller than the sum of its proper divisors (3282551568).

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

1981917312 is an equidigital number, since it uses as much as digits as its factorization.

1981917312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5161260 (or 5161248 counting only the distinct ones).

The product of its digits is 27216, while the sum is 42.

The square root of 1981917312 is about 44518.7299010203. The cubic root of 1981917312 is about 1256.1124218140.

The spelling of 1981917312 in words is "one billion, nine hundred eighty-one million, nine hundred seventeen thousand, three hundred twelve".