211100021261 has 2 divisors, whose sum is σ = 211100021262. Its totient is φ = 211100021260.

The previous prime is 211100021213. The next prime is 211100021267. The reversal of 211100021261 is 162120001112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 144468408100 + 66631613161 = 380090^2 + 258131^2 .

It is a cyclic number.

It is not a de Polignac number, because 211100021261 - 2³⁴ = 193920152077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211100021267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105550010630 + 105550010631.

It is an arithmetic number, because the mean of its divisors is an integer number (105550010631).

Almost surely, 2^211100021261 is an apocalyptic number.

It is an amenable number.

211100021261 is a deficient number, since it is larger than the sum of its proper divisors (1).

211100021261 is an equidigital number, since it uses as much as digits as its factorization.

211100021261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 211100021261 its reverse (162120001112), we get a palindrome (373220022373).

The spelling of 211100021261 in words is "two hundred eleven billion, one hundred million, twenty-one thousand, two hundred sixty-one".