212115209 has 4 divisors (see below), whose sum is σ = 212192916. Its totient is φ = 212037504.

The previous prime is 212115139. The next prime is 212115227. The reversal of 212115209 is 902511212.

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 38402809 + 173712400 = 6197^2 + 13180^2 .

It is a cyclic number.

It is not a de Polignac number, because 212115209 - 2⁸ = 212114953 is a prime.

It is a super-2 number, since 2×212115209² = 89985723778227362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212115289) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34604 + ... + 40269.

It is an arithmetic number, because the mean of its divisors is an integer number (53048229).

Almost surely, 2^212115209 is an apocalyptic number.

It is an amenable number.

212115209 is a deficient number, since it is larger than the sum of its proper divisors (77707).

212115209 is an equidigital number, since it uses as much as digits as its factorization.

212115209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77706.

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 212115209 is about 14564.1755345093. The cubic root of 212115209 is about 596.3811888535.

The spelling of 212115209 in words is "two hundred twelve million, one hundred fifteen thousand, two hundred nine".