205621123 has 2 divisors, whose sum is σ = 205621124. Its totient is φ = 205621122.

The previous prime is 205621093. The next prime is 205621133. The reversal of 205621123 is 321126502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 205621123 - 2¹³ = 205612931 is a prime.

It is a super-2 number, since 2×205621123² = 84560092447562258, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 205621094 and 205621103.

It is not a weakly prime, because it can be changed into another prime (205621133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102810561 + 102810562.

It is an arithmetic number, because the mean of its divisors is an integer number (102810562).

Almost surely, 2^205621123 is an apocalyptic number.

205621123 is a deficient number, since it is larger than the sum of its proper divisors (1).

205621123 is an equidigital number, since it uses as much as digits as its factorization.

205621123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 205621123 is about 14339.4952142675. The cubic root of 205621123 is about 590.2317609071.

Adding to 205621123 its reverse (321126502), we get a palindrome (526747625).

The spelling of 205621123 in words is "two hundred five million, six hundred twenty-one thousand, one hundred twenty-three".