212102381 has 2 divisors, whose sum is σ = 212102382. Its totient is φ = 212102380.

The previous prime is 212102329. The next prime is 212102393. The reversal of 212102381 is 183201212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 137124100 + 74978281 = 11710^2 + 8659^2 .

It is a cyclic number.

It is not a de Polignac number, because 212102381 - 2²⁶ = 144993517 is a prime.

It is a super-2 number, since 2×212102381² = 89974840051738322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212102321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106051190 + 106051191.

It is an arithmetic number, because the mean of its divisors is an integer number (106051191).

Almost surely, 2^212102381 is an apocalyptic number.

It is an amenable number.

212102381 is a deficient number, since it is larger than the sum of its proper divisors (1).

212102381 is an equidigital number, since it uses as much as digits as its factorization.

212102381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 212102381 is about 14563.7351321699. The cubic root of 212102381 is about 596.3691662485.

Adding to 212102381 its reverse (183201212), we get a palindrome (395303593).

The spelling of 212102381 in words is "two hundred twelve million, one hundred two thousand, three hundred eighty-one".