261630211 has 2 divisors, whose sum is σ = 261630212. Its totient is φ = 261630210.

The previous prime is 261630203. The next prime is 261630233. The reversal of 261630211 is 112036162.

It is an a-pointer prime, because the next prime (261630233) can be obtained adding 261630211 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261630211 - 2³ = 261630203 is a prime.

It is not a weakly prime, because it can be changed into another prime (261630241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130815105 + 130815106.

It is an arithmetic number, because the mean of its divisors is an integer number (130815106).

Almost surely, 2^261630211 is an apocalyptic number.

261630211 is a deficient number, since it is larger than the sum of its proper divisors (1).

261630211 is an equidigital number, since it uses as much as digits as its factorization.

261630211 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 261630211 is about 16174.9872024679. The cubic root of 261630211 is about 639.5816039772.

Adding to 261630211 its reverse (112036162), we get a palindrome (373666373).

The spelling of 261630211 in words is "two hundred sixty-one million, six hundred thirty thousand, two hundred eleven".