212040209 has 12 divisors (see below), whose sum is σ = 227479860. Its totient is φ = 197566560.

The previous prime is 212040203. The next prime is 212040221. The reversal of 212040209 is 902040212.

It can be written as a sum of positive squares in 2 ways, for example, as 114425809 + 97614400 = 10697^2 + 9880^2 .

It is not a de Polignac number, because 212040209 - 2¹⁶ = 211974673 is a prime.

It is a super-2 number, since 2×212040209² = 89922100465527362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (212040203) 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 11 ways as a sum of consecutive naturals, for example, 17207 + ... + 26835.

It is an arithmetic number, because the mean of its divisors is an integer number (18956655).

Almost surely, 2^212040209 is an apocalyptic number.

It is an amenable number.

212040209 is a deficient number, since it is larger than the sum of its proper divisors (15439651).

212040209 is an equidigital number, since it uses as much as digits as its factorization.

212040209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9728 (or 9709 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 212040209 is about 14561.6004958246. The cubic root of 212040209 is about 596.3108907953.

The spelling of 212040209 in words is "two hundred twelve million, forty thousand, two hundred nine".