1981312 has 32 divisors (see below), whose sum is σ = 4124880. Its totient is φ = 946176.

The previous prime is 1981297. The next prime is 1981337. The reversal of 1981312 is 2131891.

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

It is a super-3 number, since 3×1981312³ = 23333498764325289984, which contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2608 + ... + 3280.

2^1981312 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 1981312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2062440).

1981312 is an abundant number, since it is smaller than the sum of its proper divisors (2143568).

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

1981312 is an equidigital number, since it uses as much as digits as its factorization.

1981312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 710 (or 698 counting only the distinct ones).

The product of its digits is 432, while the sum is 25.

The square root of 1981312 is about 1407.5908496435. The cubic root of 1981312 is about 125.5984529270.

The spelling of 1981312 in words is "one million, nine hundred eighty-one thousand, three hundred twelve".