221991229 has 4 divisors (see below), whose sum is σ = 222229084. Its totient is φ = 221753376.

The previous prime is 221991221. The next prime is 221991247. The reversal of 221991229 is 922199122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 44488900 + 177502329 = 6670^2 + 13323^2 .

It is a cyclic number.

It is not a de Polignac number, because 221991229 - 2³ = 221991221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221991221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 117522 + ... + 119395.

It is an arithmetic number, because the mean of its divisors is an integer number (55557271).

Almost surely, 2^221991229 is an apocalyptic number.

It is an amenable number.

221991229 is a deficient number, since it is larger than the sum of its proper divisors (237855).

221991229 is an equidigital number, since it uses as much as digits as its factorization.

221991229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237854.

The product of its digits is 11664, while the sum is 37.

The square root of 221991229 is about 14899.3700873560. The cubic root of 221991229 is about 605.4969202466.

The spelling of 221991229 in words is "two hundred twenty-one million, nine hundred ninety-one thousand, two hundred twenty-nine".