205420405 has 8 divisors (see below), whose sum is σ = 246963384. Its totient is φ = 164030400.

The previous prime is 205420363. The next prime is 205420433. The reversal of 205420405 is 504024502.

It can be written as a sum of positive squares in 4 ways, for example, as 43850884 + 161569521 = 6622^2 + 12711^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 205420405 - 2¹¹ = 205418357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35266 + ... + 40675.

It is an arithmetic number, because the mean of its divisors is an integer number (30870423).

Almost surely, 2^205420405 is an apocalyptic number.

It is an amenable number.

205420405 is a deficient number, since it is larger than the sum of its proper divisors (41542979).

205420405 is an equidigital number, since it uses as much as digits as its factorization.

205420405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76487.

The product of its (nonzero) digits is 1600, while the sum is 22.

The square root of 205420405 is about 14332.4947235295. The cubic root of 205420405 is about 590.0396459043.

Adding to 205420405 its reverse (504024502), we get a palindrome (709444907).

The spelling of 205420405 in words is "two hundred five million, four hundred twenty thousand, four hundred five".