212239721 has 2 divisors, whose sum is σ = 212239722. Its totient is φ = 212239720.

The previous prime is 212239717. The next prime is 212239759. The reversal of 212239721 is 127932212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 184824025 + 27415696 = 13595^2 + 5236^2 .

It is a cyclic number.

It is not a de Polignac number, because 212239721 - 2² = 212239717 is a prime.

It is not a weakly prime, because it can be changed into another prime (212239021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106119860 + 106119861.

It is an arithmetic number, because the mean of its divisors is an integer number (106119861).

Almost surely, 2^212239721 is an apocalyptic number.

It is an amenable number.

212239721 is a deficient number, since it is larger than the sum of its proper divisors (1).

212239721 is an equidigital number, since it uses as much as digits as its factorization.

212239721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 29.

The square root of 212239721 is about 14568.4495056955. The cubic root of 212239721 is about 596.4978582963.

The spelling of 212239721 in words is "two hundred twelve million, two hundred thirty-nine thousand, seven hundred twenty-one".