21200209993 has 2 divisors, whose sum is σ = 21200209994. Its totient is φ = 21200209992.

The previous prime is 21200209991. The next prime is 21200210029. The reversal of 21200209993 is 39990200212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11606399289 + 9593810704 = 107733^2 + 97948^2 .

It is a cyclic number.

It is not a de Polignac number, because 21200209993 - 2¹ = 21200209991 is a prime.

Together with 21200209991, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21200209991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600104996 + 10600104997.

It is an arithmetic number, because the mean of its divisors is an integer number (10600104997).

Almost surely, 2^21200209993 is an apocalyptic number.

It is an amenable number.

21200209993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21200209993 is an equidigital number, since it uses as much as digits as its factorization.

21200209993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17496, while the sum is 37.

The spelling of 21200209993 in words is "twenty-one billion, two hundred million, two hundred nine thousand, nine hundred ninety-three".