221201261 has 2 divisors, whose sum is σ = 221201262. Its totient is φ = 221201260.

The previous prime is 221201257. The next prime is 221201329. The reversal of 221201261 is 162102122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 158886025 + 62315236 = 12605^2 + 7894^2 .

It is a cyclic number.

It is not a de Polignac number, because 221201261 - 2² = 221201257 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221204261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110600630 + 110600631.

It is an arithmetic number, because the mean of its divisors is an integer number (110600631).

Almost surely, 2^221201261 is an apocalyptic number.

It is an amenable number.

221201261 is a deficient number, since it is larger than the sum of its proper divisors (1).

221201261 is an equidigital number, since it uses as much as digits as its factorization.

221201261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 221201261 is about 14872.8363468439. The cubic root of 221201261 is about 604.7778352368. Note that the first 3 decimals are identical.

Adding to 221201261 its reverse (162102122), we get a palindrome (383303383).

The spelling of 221201261 in words is "two hundred twenty-one million, two hundred one thousand, two hundred sixty-one".