21101009999 has 2 divisors, whose sum is σ = 21101010000. Its totient is φ = 21101009998.

The previous prime is 21101009981. The next prime is 21101010013. The reversal of 21101009999 is 99990010112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21101009999 - 2¹² = 21101005903 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101009959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550504999 + 10550505000.

It is an arithmetic number, because the mean of its divisors is an integer number (10550505000).

Almost surely, 2^21101009999 is an apocalyptic number.

21101009999 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101009999 is an equidigital number, since it uses as much as digits as its factorization.

21101009999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13122, while the sum is 41.

The spelling of 21101009999 in words is "twenty-one billion, one hundred one million, nine thousand, nine hundred ninety-nine".