221601561303555 has 256 divisors, whose sum is σ = 419714555904000. Its totient is φ = 110748404736000.

The previous prime is 221601561303481. The next prime is 221601561303559. The reversal of 221601561303555 is 555303165106122.

221601561303555 is a `hidden beast` number, since 2 + 2 + 1 + 6 + 0 + 1 + 5 + 61 + 30 + 3 + 555 = 666.

It is not a de Polignac number, because 221601561303555 - 2¹⁵ = 221601561270787 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 221601561303555.

It is not an unprimeable number, because it can be changed into a prime (221601561303559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 42363132790 + ... + 42363138020.

It is an arithmetic number, because the mean of its divisors is an integer number (1639509984000).

Almost surely, 2^{221601561303555} is an apocalyptic number.

221601561303555 is a deficient number, since it is larger than the sum of its proper divisors (198112994600445).

221601561303555 is a wasteful number, since it uses less digits than its factorization.

221601561303555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7123 (or 7117 counting only the distinct ones).

The product of its (nonzero) digits is 810000, while the sum is 45.

The spelling of 221601561303555 in words is "two hundred twenty-one trillion, six hundred one billion, five hundred sixty-one million, three hundred three thousand, five hundred fifty-five".