212393821 has 2 divisors, whose sum is σ = 212393822. Its totient is φ = 212393820.

The previous prime is 212393789. The next prime is 212393827. The reversal of 212393821 is 128393212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 176225625 + 36168196 = 13275^2 + 6014^2 .

It is a cyclic number.

It is not a de Polignac number, because 212393821 - 2⁵ = 212393789 is a prime.

It is a super-2 number, since 2×212393821² = 90222270397960082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212393827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106196910 + 106196911.

It is an arithmetic number, because the mean of its divisors is an integer number (106196911).

Almost surely, 2^212393821 is an apocalyptic number.

It is an amenable number.

212393821 is a deficient number, since it is larger than the sum of its proper divisors (1).

212393821 is an equidigital number, since it uses as much as digits as its factorization.

212393821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 31.

The square root of 212393821 is about 14573.7373724107. The cubic root of 212393821 is about 596.6421889330.

The spelling of 212393821 in words is "two hundred twelve million, three hundred ninety-three thousand, eight hundred twenty-one".