212878381 has 2 divisors, whose sum is σ = 212878382. Its totient is φ = 212878380.

The previous prime is 212878343. The next prime is 212878387. The reversal of 212878381 is 183878212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 188622756 + 24255625 = 13734^2 + 4925^2 .

It is a cyclic number.

It is not a de Polignac number, because 212878381 - 2¹¹ = 212876333 is a prime.

It is a super-2 number, since 2×212878381² = 90634410194362322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212878387) 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, 106439190 + 106439191.

It is an arithmetic number, because the mean of its divisors is an integer number (106439191).

Almost surely, 2^212878381 is an apocalyptic number.

It is an amenable number.

212878381 is a deficient number, since it is larger than the sum of its proper divisors (1).

212878381 is an equidigital number, since it uses as much as digits as its factorization.

212878381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43008, while the sum is 40.

The square root of 212878381 is about 14590.3523261092. The cubic root of 212878381 is about 597.0955752511.

The spelling of 212878381 in words is "two hundred twelve million, eight hundred seventy-eight thousand, three hundred eighty-one".