205436621 has 12 divisors (see below), whose sum is σ = 231284508. Its totient is φ = 181382784.

The previous prime is 205436603. The next prime is 205436641. The reversal of 205436621 is 126634502.

It can be written as a sum of positive squares in 2 ways, for example, as 122899396 + 82537225 = 11086^2 + 9085^2 .

It is not a de Polignac number, because 205436621 - 2²² = 201242317 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205436641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8060 + ... + 21813.

It is an arithmetic number, because the mean of its divisors is an integer number (19273709).

Almost surely, 2^205436621 is an apocalyptic number.

It is an amenable number.

205436621 is a deficient number, since it is larger than the sum of its proper divisors (25847887).

205436621 is a wasteful number, since it uses less digits than its factorization.

205436621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29932 (or 29909 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 205436621 is about 14333.0604198824. The cubic root of 205436621 is about 590.0551715141.

The spelling of 205436621 in words is "two hundred five million, four hundred thirty-six thousand, six hundred twenty-one".