221401261 has 2 divisors, whose sum is σ = 221401262. Its totient is φ = 221401260.

The previous prime is 221401199. The next prime is 221401277. The reversal of 221401261 is 162104122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 192349161 + 29052100 = 13869^2 + 5390^2 .

It is a cyclic number.

It is not a de Polignac number, because 221401261 - 2⁷ = 221401133 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 (221401291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110700630 + 110700631.

It is an arithmetic number, because the mean of its divisors is an integer number (110700631).

Almost surely, 2^221401261 is an apocalyptic number.

It is an amenable number.

221401261 is a deficient number, since it is larger than the sum of its proper divisors (1).

221401261 is an equidigital number, since it uses as much as digits as its factorization.

221401261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 221401261 is about 14879.5584947941. The cubic root of 221401261 is about 604.9600510926.

Adding to 221401261 its reverse (162104122), we get a palindrome (383505383).

The spelling of 221401261 in words is "two hundred twenty-one million, four hundred one thousand, two hundred sixty-one".