989773981 has 12 divisors (see below), whose sum is σ = 1156324572. Its totient is φ = 844726848.

The previous prime is 989773969. The next prime is 989773991. The reversal of 989773981 is 189377989.

It can be written as a sum of positive squares in 2 ways, for example, as 394657956 + 595116025 = 19866^2 + 24395^2 .

It is not a de Polignac number, because 989773981 - 2¹¹ = 989771933 is a prime.

It is a super-2 number, since 2×989773981² = 1959305066929176722, 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 (989773991) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 31930 + ... + 54763.

It is an arithmetic number, because the mean of its divisors is an integer number (96360381).

Almost surely, 2^989773981 is an apocalyptic number.

It is an amenable number.

989773981 is a deficient number, since it is larger than the sum of its proper divisors (166550591).

989773981 is a wasteful number, since it uses less digits than its factorization.

989773981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86940 (or 86933 counting only the distinct ones).

The product of its digits is 6858432, while the sum is 61.

The square root of 989773981 is about 31460.6735624017. The cubic root of 989773981 is about 996.5796414857.

The spelling of 989773981 in words is "nine hundred eighty-nine million, seven hundred seventy-three thousand, nine hundred eighty-one".