1811100100021 has 2 divisors, whose sum is σ = 1811100100022. Its totient is φ = 1811100100020.

The previous prime is 1811100099973. The next prime is 1811100100027. The reversal of 1811100100021 is 1200010011181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1742043618225 + 69056481796 = 1319865^2 + 262786^2 .

It is a cyclic number.

It is not a de Polignac number, because 1811100100021 - 2¹¹ = 1811100097973 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1811100099968 and 1811100100004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1811100100027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 905550050010 + 905550050011.

It is an arithmetic number, because the mean of its divisors is an integer number (905550050011).

Almost surely, 2^{1811100100021} is an apocalyptic number.

It is an amenable number.

1811100100021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1811100100021 is an equidigital number, since it uses as much as digits as its factorization.

1811100100021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 16.

The spelling of 1811100100021 in words is "one trillion, eight hundred eleven billion, one hundred million, one hundred thousand, twenty-one".