221641549 has 2 divisors, whose sum is σ = 221641550. Its totient is φ = 221641548.

The previous prime is 221641493. The next prime is 221641621. The reversal of 221641549 is 945146122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 113273449 + 108368100 = 10643^2 + 10410^2 .

It is a cyclic number.

It is not a de Polignac number, because 221641549 - 2⁷ = 221641421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221641249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110820774 + 110820775.

It is an arithmetic number, because the mean of its divisors is an integer number (110820775).

Almost surely, 2^221641549 is an apocalyptic number.

It is an amenable number.

221641549 is a deficient number, since it is larger than the sum of its proper divisors (1).

221641549 is an equidigital number, since it uses as much as digits as its factorization.

221641549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 34.

The square root of 221641549 is about 14887.6307383008. The cubic root of 221641549 is about 605.1788274498.

The spelling of 221641549 in words is "two hundred twenty-one million, six hundred forty-one thousand, five hundred forty-nine".