21383081749 has 2 divisors, whose sum is σ = 21383081750. Its totient is φ = 21383081748.

The previous prime is 21383081747. The next prime is 21383081767. The reversal of 21383081749 is 94718038312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21299359249 + 83722500 = 145943^2 + 9150^2 .

It is a cyclic number.

It is not a de Polignac number, because 21383081749 - 2¹ = 21383081747 is a prime.

Together with 21383081747, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21383081699 and 21383081708.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21383081743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10691540874 + 10691540875.

It is an arithmetic number, because the mean of its divisors is an integer number (10691540875).

Almost surely, 2^21383081749 is an apocalyptic number.

It is an amenable number.

21383081749 is a deficient number, since it is larger than the sum of its proper divisors (1).

21383081749 is an equidigital number, since it uses as much as digits as its factorization.

21383081749 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 290304, while the sum is 46.

The spelling of 21383081749 in words is "twenty-one billion, three hundred eighty-three million, eighty-one thousand, seven hundred forty-nine".