221331989 has 2 divisors, whose sum is σ = 221331990. Its totient is φ = 221331988.

The previous prime is 221331983. The next prime is 221332019. The reversal of 221331989 is 989133122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 218152900 + 3179089 = 14770^2 + 1783^2 .

It is a cyclic number.

It is not a de Polignac number, because 221331989 - 2¹⁶ = 221266453 is a prime.

It is a super-2 number, since 2×221331989² = 97975698709392242, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221331983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110665994 + 110665995.

It is an arithmetic number, because the mean of its divisors is an integer number (110665995).

Almost surely, 2^221331989 is an apocalyptic number.

It is an amenable number.

221331989 is a deficient number, since it is larger than the sum of its proper divisors (1).

221331989 is an equidigital number, since it uses as much as digits as its factorization.

221331989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 38.

The square root of 221331989 is about 14877.2305554495. The cubic root of 221331989 is about 604.8969512351.

The spelling of 221331989 in words is "two hundred twenty-one million, three hundred thirty-one thousand, nine hundred eighty-nine".