989816781961 has 24 divisors (see below), whose sum is σ = 1155824397000. Its totient is φ = 845174179584.

The previous prime is 989816781953. The next prime is 989816782001. The reversal of 989816781961 is 169187618989.

It can be written as a sum of positive squares in 4 ways, for example, as 280920140361 + 708896641600 = 530019^2 + 841960^2 .

It is not a de Polignac number, because 989816781961 - 2³ = 989816781953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (989816782961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15388255 + ... + 15452443.

It is an arithmetic number, because the mean of its divisors is an integer number (48159349875).

Almost surely, 2^989816781961 is an apocalyptic number.

It is an amenable number.

989816781961 is a deficient number, since it is larger than the sum of its proper divisors (166007615039).

989816781961 is a wasteful number, since it uses less digits than its factorization.

989816781961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65401 (or 65394 counting only the distinct ones).

The product of its digits is 94058496, while the sum is 73.

The spelling of 989816781961 in words is "nine hundred eighty-nine billion, eight hundred sixteen million, seven hundred eighty-one thousand, nine hundred sixty-one".