1981568 has 32 divisors (see below), whose sum is σ = 4011660. Its totient is φ = 974848.

The previous prime is 1981547. The next prime is 1981583. The reversal of 1981568 is 8651891.

It can be written as a sum of positive squares in 2 ways, for example, as 1827904 + 153664 = 1352^2 + 392^2 .

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

It is a super-2 number, since 2×1981568² = 7853223477248, which contains 22 as substring.

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, 14396 + ... + 14532.

2^1981568 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 1981568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2005830).

1981568 is an abundant number, since it is smaller than the sum of its proper divisors (2030092).

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

1981568 is a wasteful number, since it uses less digits than its factorization.

1981568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 264 (or 252 counting only the distinct ones).

The product of its digits is 17280, while the sum is 38.

The square root of 1981568 is about 1407.6817822221. The cubic root of 1981568 is about 125.6038621069.

The spelling of 1981568 in words is "one million, nine hundred eighty-one thousand, five hundred sixty-eight".