211421209261 has 2 divisors, whose sum is σ = 211421209262. Its totient is φ = 211421209260.

The previous prime is 211421209231. The next prime is 211421209271. The reversal of 211421209261 is 162902124112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 163777233636 + 47643975625 = 404694^2 + 218275^2 .

It is a cyclic number.

It is not a de Polignac number, because 211421209261 - 2¹¹ = 211421207213 is a prime.

It is a super-4 number, since 4×211421209261⁴ (a number of 46 digits) contains 4444 as substring. Note that it is a super-d number also for d = 3, 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211421209211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105710604630 + 105710604631.

It is an arithmetic number, because the mean of its divisors is an integer number (105710604631).

Almost surely, 2^211421209261 is an apocalyptic number.

It is an amenable number.

211421209261 is a deficient number, since it is larger than the sum of its proper divisors (1).

211421209261 is an equidigital number, since it uses as much as digits as its factorization.

211421209261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 31.

The spelling of 211421209261 in words is "two hundred eleven billion, four hundred twenty-one million, two hundred nine thousand, two hundred sixty-one".