212203721 has 2 divisors, whose sum is σ = 212203722. Its totient is φ = 212203720.

The previous prime is 212203709. The next prime is 212203729. The reversal of 212203721 is 127302212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 106915600 + 105288121 = 10340^2 + 10261^2 .

It is a cyclic number.

It is not a de Polignac number, because 212203721 - 2¹⁸ = 211941577 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 212203693 and 212203702.

It is not a weakly prime, because it can be changed into another prime (212203729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106101860 + 106101861.

It is an arithmetic number, because the mean of its divisors is an integer number (106101861).

Almost surely, 2^212203721 is an apocalyptic number.

It is an amenable number.

212203721 is a deficient number, since it is larger than the sum of its proper divisors (1).

212203721 is an equidigital number, since it uses as much as digits as its factorization.

212203721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 212203721 is about 14567.2139065780. The cubic root of 212203721 is about 596.4641304954.

Adding to 212203721 its reverse (127302212), we get a palindrome (339505933).

The spelling of 212203721 in words is "two hundred twelve million, two hundred three thousand, seven hundred twenty-one".