1100100001981 has 2 divisors, whose sum is σ = 1100100001982. Its totient is φ = 1100100001980.

The previous prime is 1100100001963. The next prime is 1100100002017. The reversal of 1100100001981 is 1891000010011.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 896600672100 + 203499329881 = 946890^2 + 451109^2 .

It is a cyclic number.

It is not a de Polignac number, because 1100100001981 - 2³⁷ = 962661048509 is a prime.

It is a super-2 number, since 2×1100100001981² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1100100001951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 550050000990 + 550050000991.

It is an arithmetic number, because the mean of its divisors is an integer number (550050000991).

Almost surely, 2^{1100100001981} is an apocalyptic number.

It is an amenable number.

1100100001981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1100100001981 is an equidigital number, since it uses as much as digits as its factorization.

1100100001981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 22.

Adding to 1100100001981 its reverse (1891000010011), we get a palindrome (2991100011992).

The spelling of 1100100001981 in words is "one trillion, one hundred billion, one hundred million, one thousand, nine hundred eighty-one".