221647123065541 has 2 divisors, whose sum is σ = 221647123065542. Its totient is φ = 221647123065540.

The previous prime is 221647123065383. The next prime is 221647123065569. The reversal of 221647123065541 is 145560321746122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 143048082393441 + 78599040672100 = 11960271^2 + 8865610^2 .

It is a cyclic number.

It is not a de Polignac number, because 221647123065541 - 2¹⁵ = 221647123032773 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221647123065941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110823561532770 + 110823561532771.

It is an arithmetic number, because the mean of its divisors is an integer number (110823561532771).

Almost surely, 2^{221647123065541} is an apocalyptic number.

It is an amenable number.

221647123065541 is a deficient number, since it is larger than the sum of its proper divisors (1).

221647123065541 is an equidigital number, since it uses as much as digits as its factorization.

221647123065541 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2419200, while the sum is 49.

The spelling of 221647123065541 in words is "two hundred twenty-one trillion, six hundred forty-seven billion, one hundred twenty-three million, sixty-five thousand, five hundred forty-one".