10999981681 has 12 divisors (see below), whose sum is σ = 12034036812. Its totient is φ = 10049135616.

The previous prime is 10999981651. The next prime is 10999981691. The reversal of 10999981681 is 18618999901.

It can be written as a sum of positive squares in 6 ways, for example, as 20295025 + 10979686656 = 4505^2 + 104784^2 .

It is not a de Polignac number, because 10999981681 - 2¹¹ = 10999979633 is a prime.

It is a super-3 number, since 3×10999981681³ (a number of 31 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (10999981651) 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, 319116 + ... + 351901.

It is an arithmetic number, because the mean of its divisors is an integer number (1002836401).

Almost surely, 2^10999981681 is an apocalyptic number.

It is an amenable number.

10999981681 is a deficient number, since it is larger than the sum of its proper divisors (1034055131).

10999981681 is an equidigital number, since it uses as much as digits as its factorization.

10999981681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 671140 (or 671127 counting only the distinct ones).

The product of its (nonzero) digits is 2519424, while the sum is 61.

The spelling of 10999981681 in words is "ten billion, nine hundred ninety-nine million, nine hundred eighty-one thousand, six hundred eighty-one".