213205805 has 8 divisors (see below), whose sum is σ = 255943800. Its totient is φ = 170500096.

The previous prime is 213205757. The next prime is 213205813. The reversal of 213205805 is 508502312.

213205805 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 6220036 + 206985769 = 2494^2 + 14387^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 213205805 - 2²² = 209011501 is a prime.

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, 10241 + ... + 23049.

It is an arithmetic number, because the mean of its divisors is an integer number (31992975).

Almost surely, 2^213205805 is an apocalyptic number.

It is an amenable number.

213205805 is a deficient number, since it is larger than the sum of its proper divisors (42737995).

213205805 is a wasteful number, since it uses less digits than its factorization.

213205805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16143.

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 213205805 is about 14601.5685801218. The cubic root of 213205805 is about 597.4015453751.

The spelling of 213205805 in words is "two hundred thirteen million, two hundred five thousand, eight hundred five".