1221105541 has 2 divisors, whose sum is σ = 1221105542. Its totient is φ = 1221105540.

The previous prime is 1221105539. The next prime is 1221105569. The reversal of 1221105541 is 1455011221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1017929025 + 203176516 = 31905^2 + 14254^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221105541 - 2¹ = 1221105539 is a prime.

Together with 1221105539, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221108541) 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, 610552770 + 610552771.

It is an arithmetic number, because the mean of its divisors is an integer number (610552771).

Almost surely, 2^1221105541 is an apocalyptic number.

It is an amenable number.

1221105541 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221105541 is an equidigital number, since it uses as much as digits as its factorization.

1221105541 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 400, while the sum is 22.

The square root of 1221105541 is about 34944.3205828930. The cubic root of 1221105541 is about 1068.8523932038.

Adding to 1221105541 its reverse (1455011221), we get a palindrome (2676116762).

The spelling of 1221105541 in words is "one billion, two hundred twenty-one million, one hundred five thousand, five hundred forty-one".