21011776349 has 2 divisors, whose sum is σ = 21011776350. Its totient is φ = 21011776348.

The previous prime is 21011776327. The next prime is 21011776351. The reversal of 21011776349 is 94367711012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20733120100 + 278656249 = 143990^2 + 16693^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21011776349 is a prime.

It is a Sophie Germain prime.

Together with 21011776351, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011776249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505888174 + 10505888175.

It is an arithmetic number, because the mean of its divisors is an integer number (10505888175).

Almost surely, 2^21011776349 is an apocalyptic number.

It is an amenable number.

21011776349 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011776349 is an equidigital number, since it uses as much as digits as its factorization.

21011776349 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63504, while the sum is 41.

The spelling of 21011776349 in words is "twenty-one billion, eleven million, seven hundred seventy-six thousand, three hundred forty-nine".