21011001919 has 2 divisors, whose sum is σ = 21011001920. Its totient is φ = 21011001918.

The previous prime is 21011001917. The next prime is 21011001931. The reversal of 21011001919 is 91910011012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21011001919 - 2¹ = 21011001917 is a prime.

It is a super-2 number, since 2×21011001919² (a number of 21 digits) contains 22 as substring.

Together with 21011001917, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21011001893 and 21011001902.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011001911) 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, 10505500959 + 10505500960.

It is an arithmetic number, because the mean of its divisors is an integer number (10505500960).

Almost surely, 2^21011001919 is an apocalyptic number.

21011001919 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011001919 is an equidigital number, since it uses as much as digits as its factorization.

21011001919 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 162, while the sum is 25.

The spelling of 21011001919 in words is "twenty-one billion, eleven million, one thousand, nine hundred nineteen".