1100999981 has 2 divisors, whose sum is σ = 1100999982. Its totient is φ = 1100999980.

The previous prime is 1100999969. The next prime is 1100999983. The reversal of 1100999981 is 1899990011.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1007491081 + 93508900 = 31741^2 + 9670^2 .

It is a cyclic number.

It is not a de Polignac number, because 1100999981 - 2¹⁰ = 1100998957 is a prime.

It is a super-2 number, since 2×1100999981² = 2424401916324000722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 1100999983, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1100999983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 550499990 + 550499991.

It is an arithmetic number, because the mean of its divisors is an integer number (550499991).

Almost surely, 2^1100999981 is an apocalyptic number.

It is an amenable number.

1100999981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1100999981 is an equidigital number, since it uses as much as digits as its factorization.

1100999981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 52488, while the sum is 47.

The square root of 1100999981 is about 33181.3197597684. The cubic root of 1100999981 is about 1032.5928269290.

The spelling of 1100999981 in words is "one billion, one hundred million, nine hundred ninety-nine thousand, nine hundred eighty-one".