21101321999 has 2 divisors, whose sum is σ = 21101322000. Its totient is φ = 21101321998.

The previous prime is 21101321977. The next prime is 21101322023. The reversal of 21101321999 is 99912310112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21101321999 - 2⁸ = 21101321743 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101321099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550660999 + 10550661000.

It is an arithmetic number, because the mean of its divisors is an integer number (10550661000).

Almost surely, 2^21101321999 is an apocalyptic number.

21101321999 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101321999 is an equidigital number, since it uses as much as digits as its factorization.

21101321999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8748, while the sum is 38.

The spelling of 21101321999 in words is "twenty-one billion, one hundred one million, three hundred twenty-one thousand, nine hundred ninety-nine".