21000111994009 has 2 divisors, whose sum is σ = 21000111994010. Its totient is φ = 21000111994008.

The previous prime is 21000111994003. The next prime is 21000111994079. The reversal of 21000111994009 is 90049911100012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10511601465600 + 10488510528409 = 3242160^2 + 3238597^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000111994009 - 2⁷ = 21000111993881 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000111994003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500055997004 + 10500055997005.

It is an arithmetic number, because the mean of its divisors is an integer number (10500055997005).

Almost surely, 2^{21000111994009} is an apocalyptic number.

It is an amenable number.

21000111994009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000111994009 is an equidigital number, since it uses as much as digits as its factorization.

21000111994009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 37.

The spelling of 21000111994009 in words is "twenty-one trillion, one hundred eleven million, nine hundred ninety-four thousand, nine".