221236009 has 2 divisors, whose sum is σ = 221236010. Its totient is φ = 221236008.

The previous prime is 221235997. The next prime is 221236013. The reversal of 221236009 is 900632122.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135210384 + 86025625 = 11628^2 + 9275^2 .

It is a cyclic number.

It is not a de Polignac number, because 221236009 - 2⁷ = 221235881 is a prime.

It is not a weakly prime, because it can be changed into another prime (221236409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110618004 + 110618005.

It is an arithmetic number, because the mean of its divisors is an integer number (110618005).

Almost surely, 2^221236009 is an apocalyptic number.

It is an amenable number.

221236009 is a deficient number, since it is larger than the sum of its proper divisors (1).

221236009 is an equidigital number, since it uses as much as digits as its factorization.

221236009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 221236009 is about 14874.0044708881. The cubic root of 221236009 is about 604.8095013009.

The spelling of 221236009 in words is "two hundred twenty-one million, two hundred thirty-six thousand, nine".