21101000021009 has 2 divisors, whose sum is σ = 21101000021010. Its totient is φ = 21101000021008.

The previous prime is 21101000020981. The next prime is 21101000021021. The reversal of 21101000021009 is 90012000010112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19713351360784 + 1387648660225 = 4439972^2 + 1177985^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101000021009 - 2¹² = 21101000016913 is a prime.

It is not a weakly prime, because it can be changed into another prime (21101000021509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550500010504 + 10550500010505.

It is an arithmetic number, because the mean of its divisors is an integer number (10550500010505).

Almost surely, 2^{21101000021009} is an apocalyptic number.

It is an amenable number.

21101000021009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101000021009 is an equidigital number, since it uses as much as digits as its factorization.

21101000021009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 17.

The spelling of 21101000021009 in words is "twenty-one trillion, one hundred one billion, twenty-one thousand, nine".