21110120021009 has 2 divisors, whose sum is σ = 21110120021010. Its totient is φ = 21110120021008.

The previous prime is 21110120020999. The next prime is 21110120021027. The reversal of 21110120021009 is 90012002101112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19071213043600 + 2038906977409 = 4367060^2 + 1427903^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110120021009 - 2⁸ = 21110120020753 is a prime.

It is not a weakly prime, because it can be changed into another prime (21110120071009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555060010504 + 10555060010505.

It is an arithmetic number, because the mean of its divisors is an integer number (10555060010505).

Almost surely, 2^{21110120021009} is an apocalyptic number.

It is an amenable number.

21110120021009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21110120021009 is an equidigital number, since it uses as much as digits as its factorization.

21110120021009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 21110120021009 in words is "twenty-one trillion, one hundred ten billion, one hundred twenty million, twenty-one thousand, nine".