221655635664436 has 6 divisors (see below), whose sum is σ = 387897362412770. Its totient is φ = 110827817832216.

The previous prime is 221655635664431. The next prime is 221655635664493. The reversal of 221655635664436 is 634466536556122.

It can be written as a sum of positive squares in only one way, i.e., 220977144090000 + 678491574436 = 14865300^2 + 823706^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221655635664431) 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 as a sum of consecutive naturals, namely, 27706954458051 + ... + 27706954458058.

Almost surely, 2^{221655635664436} is an apocalyptic number.

It is an amenable number.

221655635664436 is a deficient number, since it is larger than the sum of its proper divisors (166241726748334).

221655635664436 is a wasteful number, since it uses less digits than its factorization.

221655635664436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55413908916113 (or 55413908916111 counting only the distinct ones).

The product of its digits is 559872000, while the sum is 64.

The spelling of 221655635664436 in words is "two hundred twenty-one trillion, six hundred fifty-five billion, six hundred thirty-five million, six hundred sixty-four thousand, four hundred thirty-six".