221536541 has 2 divisors, whose sum is σ = 221536542. Its totient is φ = 221536540.

The previous prime is 221536517. The next prime is 221536573. The reversal of 221536541 is 145635122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 207504025 + 14032516 = 14405^2 + 3746^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221536541 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 (221536141) 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, 110768270 + 110768271.

It is an arithmetic number, because the mean of its divisors is an integer number (110768271).

Almost surely, 2^221536541 is an apocalyptic number.

It is an amenable number.

221536541 is a deficient number, since it is larger than the sum of its proper divisors (1).

221536541 is an equidigital number, since it uses as much as digits as its factorization.

221536541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7200, while the sum is 29.

The square root of 221536541 is about 14884.1036344148. The cubic root of 221536541 is about 605.0832396909.

The spelling of 221536541 in words is "two hundred twenty-one million, five hundred thirty-six thousand, five hundred forty-one".