21112101949 has 2 divisors, whose sum is σ = 21112101950. Its totient is φ = 21112101948.

The previous prime is 21112101947. The next prime is 21112101953. The reversal of 21112101949 is 94910121112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20723617849 + 388484100 = 143957^2 + 19710^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112101949 - 2¹ = 21112101947 is a prime.

Together with 21112101947, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21112101949.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21112101947) 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, 10556050974 + 10556050975.

It is an arithmetic number, because the mean of its divisors is an integer number (10556050975).

Almost surely, 2^21112101949 is an apocalyptic number.

It is an amenable number.

21112101949 is a deficient number, since it is larger than the sum of its proper divisors (1).

21112101949 is an equidigital number, since it uses as much as digits as its factorization.

21112101949 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 31.

The spelling of 21112101949 in words is "twenty-one billion, one hundred twelve million, one hundred one thousand, nine hundred forty-nine".