205541989 has 2 divisors, whose sum is σ = 205541990. Its totient is φ = 205541988.

The previous prime is 205541983. The next prime is 205542011. The reversal of 205541989 is 989145502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 152324964 + 53217025 = 12342^2 + 7295^2 .

It is a cyclic number.

It is not a de Polignac number, because 205541989 - 2¹⁵ = 205509221 is a prime.

It is a super-2 number, since 2×205541989² = 84495018484152242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205541983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102770994 + 102770995.

It is an arithmetic number, because the mean of its divisors is an integer number (102770995).

Almost surely, 2^205541989 is an apocalyptic number.

It is an amenable number.

205541989 is a deficient number, since it is larger than the sum of its proper divisors (1).

205541989 is an equidigital number, since it uses as much as digits as its factorization.

205541989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 129600, while the sum is 43.

The square root of 205541989 is about 14336.7356465829. The cubic root of 205541989 is about 590.1560336138.

It can be divided in two parts, 2055 and 41989, that added together give a palindrome (44044).

The spelling of 205541989 in words is "two hundred five million, five hundred forty-one thousand, nine hundred eighty-nine".