221553989 has 2 divisors, whose sum is σ = 221553990. Its totient is φ = 221553988.

The previous prime is 221553971. The next prime is 221554031. The reversal of 221553989 is 989355122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 114597025 + 106956964 = 10705^2 + 10342^2 .

It is a cyclic number.

It is not a de Polignac number, because 221553989 - 2²⁰ = 220505413 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 (221553929) 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, 110776994 + 110776995.

It is an arithmetic number, because the mean of its divisors is an integer number (110776995).

Almost surely, 2^221553989 is an apocalyptic number.

It is an amenable number.

221553989 is a deficient number, since it is larger than the sum of its proper divisors (1).

221553989 is an equidigital number, since it uses as much as digits as its factorization.

221553989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 194400, while the sum is 44.

The square root of 221553989 is about 14884.6897515534. The cubic root of 221553989 is about 605.0991245274.

The spelling of 221553989 in words is "two hundred twenty-one million, five hundred fifty-three thousand, nine hundred eighty-nine".