211870261 has 2 divisors, whose sum is σ = 211870262. Its totient is φ = 211870260.

The previous prime is 211870237. The next prime is 211870289. The reversal of 211870261 is 162078112.

It is an a-pointer prime, because the next prime (211870289) can be obtained adding 211870261 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 201469636 + 10400625 = 14194^2 + 3225^2 .

It is a cyclic number.

It is not a de Polignac number, because 211870261 - 2⁵ = 211870229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211870661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105935130 + 105935131.

It is an arithmetic number, because the mean of its divisors is an integer number (105935131).

Almost surely, 2^211870261 is an apocalyptic number.

It is an amenable number.

211870261 is a deficient number, since it is larger than the sum of its proper divisors (1).

211870261 is an equidigital number, since it uses as much as digits as its factorization.

211870261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 28.

The square root of 211870261 is about 14555.7638411730. The cubic root of 211870261 is about 596.1515359091.

The spelling of 211870261 in words is "two hundred eleven million, eight hundred seventy thousand, two hundred sixty-one".