212402381 has 2 divisors, whose sum is σ = 212402382. Its totient is φ = 212402380.

The previous prime is 212402357. The next prime is 212402417. The reversal of 212402381 is 183204212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 167055625 + 45346756 = 12925^2 + 6734^2 .

It is a cyclic number.

It is not a de Polignac number, because 212402381 - 2¹⁸ = 212140237 is a prime.

It is a super-2 number, since 2×212402381² = 90229542908938322, which contains 22 as substring.

It is a Sophie Germain 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 (212402321) by changing a digit.

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 as a sum of consecutive naturals, namely, 106201190 + 106201191.

It is an arithmetic number, because the mean of its divisors is an integer number (106201191).

Almost surely, 2^212402381 is an apocalyptic number.

It is an amenable number.

212402381 is a deficient number, since it is larger than the sum of its proper divisors (1).

212402381 is an equidigital number, since it uses as much as digits as its factorization.

212402381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 212402381 is about 14574.0310484094. The cubic root of 212402381 is about 596.6502042141.

Adding to 212402381 its reverse (183204212), we get a palindrome (395606593).

The spelling of 212402381 in words is "two hundred twelve million, four hundred two thousand, three hundred eighty-one".