211213021 has 2 divisors, whose sum is σ = 211213022. Its totient is φ = 211213020.

The previous prime is 211213007. The next prime is 211213031. The reversal of 211213021 is 120312112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 165122500 + 46090521 = 12850^2 + 6789^2 .

It is a cyclic number.

It is not a de Polignac number, because 211213021 - 2⁷ = 211212893 is a prime.

It is a super-2 number, since 2×211213021² = 89221880479892882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 211212992 and 211213010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211213031) 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, 105606510 + 105606511.

It is an arithmetic number, because the mean of its divisors is an integer number (105606511).

Almost surely, 2^211213021 is an apocalyptic number.

It is an amenable number.

211213021 is a deficient number, since it is larger than the sum of its proper divisors (1).

211213021 is an equidigital number, since it uses as much as digits as its factorization.

211213021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 211213021 is about 14533.1696818003. The cubic root of 211213021 is about 595.5344594004.

Adding to 211213021 its reverse (120312112), we get a palindrome (331525133).

Subtracting from 211213021 its reverse (120312112), we obtain a palindrome (90900909).

It can be divided in two parts, 21121 and 3021, that added together give a palindrome (24142).

The spelling of 211213021 in words is "two hundred eleven million, two hundred thirteen thousand, twenty-one".