221875909 has 2 divisors, whose sum is σ = 221875910. Its totient is φ = 221875908.

The previous prime is 221875883. The next prime is 221875919. The reversal of 221875909 is 909578122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 221861025 + 14884 = 14895^2 + 122^2 .

It is a cyclic number.

It is not a de Polignac number, because 221875909 - 2⁵ = 221875877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221875919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110937954 + 110937955.

It is an arithmetic number, because the mean of its divisors is an integer number (110937955).

Almost surely, 2^221875909 is an apocalyptic number.

It is an amenable number.

221875909 is a deficient number, since it is larger than the sum of its proper divisors (1).

221875909 is an equidigital number, since it uses as much as digits as its factorization.

221875909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90720, while the sum is 43.

The square root of 221875909 is about 14895.4996223692. The cubic root of 221875909 is about 605.3920542426.

It can be divided in two parts, 221875 and 909, that added together give a square (222784 = 472²).

The spelling of 221875909 in words is "two hundred twenty-one million, eight hundred seventy-five thousand, nine hundred nine".