9881981 has 4 divisors (see below), whose sum is σ = 10463292. Its totient is φ = 9300672.

The previous prime is 9881951. The next prime is 9881983. The reversal of 9881981 is 1891889.

It is a happy number.

9881981 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7022500 + 2859481 = 2650^2 + 1691^2 .

It is a cyclic number.

It is not a de Polignac number, because 9881981 - 2¹⁸ = 9619837 is a prime.

It is a super-2 number, since 2×9881981² = 195307096968722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9881983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 290630 + ... + 290663.

It is an arithmetic number, because the mean of its divisors is an integer number (2615823).

Almost surely, 2^9881981 is an apocalyptic number.

It is an amenable number.

9881981 is a deficient number, since it is larger than the sum of its proper divisors (581311).

9881981 is a wasteful number, since it uses less digits than its factorization.

9881981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 581310.

The product of its digits is 41472, while the sum is 44.

The square root of 9881981 is about 3143.5618333349. The cubic root of 9881981 is about 214.5925653195.

The spelling of 9881981 in words is "nine million, eight hundred eighty-one thousand, nine hundred eighty-one".