21375567349 has 2 divisors, whose sum is σ = 21375567350. Its totient is φ = 21375567348.

The previous prime is 21375567329. The next prime is 21375567377. The reversal of 21375567349 is 94376557312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21262889124 + 112678225 = 145818^2 + 10615^2 .

It is a cyclic number.

It is not a de Polignac number, because 21375567349 - 2¹¹ = 21375565301 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21375567296 and 21375567305.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21375567329) 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, 10687783674 + 10687783675.

It is an arithmetic number, because the mean of its divisors is an integer number (10687783675).

Almost surely, 2^21375567349 is an apocalyptic number.

It is an amenable number.

21375567349 is a deficient number, since it is larger than the sum of its proper divisors (1).

21375567349 is an equidigital number, since it uses as much as digits as its factorization.

21375567349 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4762800, while the sum is 52.

The spelling of 21375567349 in words is "twenty-one billion, three hundred seventy-five million, five hundred sixty-seven thousand, three hundred forty-nine".