212730305 has 4 divisors (see below), whose sum is σ = 255276372. Its totient is φ = 170184240.

The previous prime is 212730233. The next prime is 212730337. The reversal of 212730305 is 503037212.

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 73891216 + 138839089 = 8596^2 + 11783^2 .

It is not a de Polignac number, because 212730305 - 2¹⁶ = 212664769 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21273026 + ... + 21273035.

It is an arithmetic number, because the mean of its divisors is an integer number (63819093).

Almost surely, 2^212730305 is an apocalyptic number.

It is an amenable number.

212730305 is a deficient number, since it is larger than the sum of its proper divisors (42546067).

212730305 is an equidigital number, since it uses as much as digits as its factorization.

212730305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42546066.

The product of its (nonzero) digits is 1260, while the sum is 23.

The square root of 212730305 is about 14585.2769942843. The cubic root of 212730305 is about 596.9570986364.

Adding to 212730305 its reverse (503037212), we get a palindrome (715767517).

The spelling of 212730305 in words is "two hundred twelve million, seven hundred thirty thousand, three hundred five".