105565721 has 2 divisors, whose sum is σ = 105565722. Its totient is φ = 105565720.

The previous prime is 105565717. The next prime is 105565727. The reversal of 105565721 is 127565501.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54228496 + 51337225 = 7364^2 + 7165^2 .

It is a cyclic number.

It is not a de Polignac number, because 105565721 - 2² = 105565717 is a prime.

It is a super-2 number, since 2×105565721² = 22288242900499682, which contains 22 as substring.

It is a Chen prime.

It is equal to p_6063278 and since 105565721 and 6063278 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (105565727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52782860 + 52782861.

It is an arithmetic number, because the mean of its divisors is an integer number (52782861).

Almost surely, 2^105565721 is an apocalyptic number.

It is an amenable number.

105565721 is a deficient number, since it is larger than the sum of its proper divisors (1).

105565721 is an equidigital number, since it uses as much as digits as its factorization.

105565721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10500, while the sum is 32.

The square root of 105565721 is about 10274.5180422247. The cubic root of 105565721 is about 472.6151503082.

The spelling of 105565721 in words is "one hundred five million, five hundred sixty-five thousand, seven hundred twenty-one".