10991026980 has 36 divisors (see below), whose sum is σ = 33339449052. Its totient is φ = 2930940480.

The previous prime is 10991026931. The next prime is 10991027009. The reversal of 10991026980 is 8962019901.

It can be written as a sum of positive squares in 2 ways, for example, as 3971268324 + 7019758656 = 63018^2 + 83784^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30530451 + ... + 30530810.

It is an arithmetic number, because the mean of its divisors is an integer number (926095807).

Almost surely, 2^10991026980 is an apocalyptic number.

10991026980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

10991026980 is an abundant number, since it is smaller than the sum of its proper divisors (22348422072).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

10991026980 is a wasteful number, since it uses less digits than its factorization.

10991026980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61061276 (or 61061271 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 45.

The spelling of 10991026980 in words is "ten billion, nine hundred ninety-one million, twenty-six thousand, nine hundred eighty".