212161409 has 2 divisors, whose sum is σ = 212161410. Its totient is φ = 212161408.

The previous prime is 212161403. The next prime is 212161423. The reversal of 212161409 is 904161212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 195580225 + 16581184 = 13985^2 + 4072^2 .

It is a cyclic number.

It is not a de Polignac number, because 212161409 - 2⁸ = 212161153 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (212161403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106080704 + 106080705.

It is an arithmetic number, because the mean of its divisors is an integer number (106080705).

Almost surely, 2^212161409 is an apocalyptic number.

It is an amenable number.

212161409 is a deficient number, since it is larger than the sum of its proper divisors (1).

212161409 is an equidigital number, since it uses as much as digits as its factorization.

212161409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 212161409 is about 14565.7615317566. The cubic root of 212161409 is about 596.4244842100.

The spelling of 212161409 in words is "two hundred twelve million, one hundred sixty-one thousand, four hundred nine".