221749811 has 2 divisors, whose sum is σ = 221749812. Its totient is φ = 221749810.

The previous prime is 221749763. The next prime is 221749849. The reversal of 221749811 is 118947122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221749811 - 2¹⁴ = 221733427 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221749861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110874905 + 110874906.

It is an arithmetic number, because the mean of its divisors is an integer number (110874906).

Almost surely, 2^221749811 is an apocalyptic number.

221749811 is a deficient number, since it is larger than the sum of its proper divisors (1).

221749811 is an equidigital number, since it uses as much as digits as its factorization.

221749811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 35.

The square root of 221749811 is about 14891.2662658352. The cubic root of 221749811 is about 605.2773456892.

The spelling of 221749811 in words is "two hundred twenty-one million, seven hundred forty-nine thousand, eight hundred eleven".