211212261 has 24 divisors (see below), whose sum is σ = 334761336. Its totient is φ = 127520640.

The previous prime is 211212247. The next prime is 211212263. The reversal of 211212261 is 162212112.

It can be written as a sum of positive squares in 4 ways, for example, as 1252161 + 209960100 = 1119^2 + 14490^2 .

It is not a de Polignac number, because 211212261 - 2¹⁴ = 211195877 is a prime.

It is a super-2 number, since 2×211212261² = 89221238393464242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211212263) 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 in 23 ways as a sum of consecutive naturals, for example, 10830 + ... + 23231.

It is an arithmetic number, because the mean of its divisors is an integer number (13948389).

Almost surely, 2^211212261 is an apocalyptic number.

It is an amenable number.

211212261 is a deficient number, since it is larger than the sum of its proper divisors (123549075).

211212261 is a wasteful number, since it uses less digits than its factorization.

211212261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34133 (or 34130 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 211212261 is about 14533.1435346934. The cubic root of 211212261 is about 595.5337451030.

Adding to 211212261 its reverse (162212112), we get a palindrome (373424373).

The spelling of 211212261 in words is "two hundred eleven million, two hundred twelve thousand, two hundred sixty-one".