989775981 has 12 divisors (see below), whose sum is σ = 1432548000. Its totient is φ = 658525320.

The previous prime is 989775979. The next prime is 989776009. The reversal of 989775981 is 189577989.

It is not a de Polignac number, because 989775981 - 2¹ = 989775979 is a prime.

It is a super-2 number, since 2×989775981² = 1959312985129024722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (989775971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 105705 + ... + 114686.

It is an arithmetic number, because the mean of its divisors is an integer number (119379000).

Almost surely, 2^989775981 is an apocalyptic number.

It is an amenable number.

989775981 is a deficient number, since it is larger than the sum of its proper divisors (442772019).

989775981 is a wasteful number, since it uses less digits than its factorization.

989775981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220896 (or 220893 counting only the distinct ones).

The product of its digits is 11430720, while the sum is 63.

The square root of 989775981 is about 31460.7053481005. The cubic root of 989775981 is about 996.5803127359.

The spelling of 989775981 in words is "nine hundred eighty-nine million, seven hundred seventy-five thousand, nine hundred eighty-one".