21312020099 has 2 divisors, whose sum is σ = 21312020100. Its totient is φ = 21312020098.

The previous prime is 21312020083. The next prime is 21312020101. The reversal of 21312020099 is 99002021312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21312020099 - 2⁴ = 21312020083 is a prime.

Together with 21312020101, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21312020069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656010049 + 10656010050.

It is an arithmetic number, because the mean of its divisors is an integer number (10656010050).

Almost surely, 2^21312020099 is an apocalyptic number.

21312020099 is a deficient number, since it is larger than the sum of its proper divisors (1).

21312020099 is an equidigital number, since it uses as much as digits as its factorization.

21312020099 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 29.

The spelling of 21312020099 in words is "twenty-one billion, three hundred twelve million, twenty thousand, ninety-nine".