213605305 has 4 divisors (see below), whose sum is σ = 256326372. Its totient is φ = 170884240.

The previous prime is 213605303. The next prime is 213605309. The reversal of 213605305 is 503506312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 73324969 + 140280336 = 8563^2 + 11844^2 .

It is not a de Polignac number, because 213605305 - 2¹ = 213605303 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 213605305.

It is not an unprimeable number, because it can be changed into a prime (213605303) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21360526 + ... + 21360535.

It is an arithmetic number, because the mean of its divisors is an integer number (64081593).

Almost surely, 2^213605305 is an apocalyptic number.

It is an amenable number.

213605305 is a deficient number, since it is larger than the sum of its proper divisors (42721067).

213605305 is an equidigital number, since it uses as much as digits as its factorization.

213605305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42721066.

The product of its (nonzero) digits is 2700, while the sum is 25.

The square root of 213605305 is about 14615.2422148933. The cubic root of 213605305 is about 597.7744448622.

The spelling of 213605305 in words is "two hundred thirteen million, six hundred five thousand, three hundred five".