221535406656 has 84 divisors (see below), whose sum is σ = 639559757200. Its totient is φ = 73313849088.

The previous prime is 221535406639. The next prime is 221535406679. The reversal of 221535406656 is 656604535122.

221535406656 is a `hidden beast` number, since 2 + 2 + 1 + 53 + 540 + 6 + 6 + 56 = 666.

It is an unprimeable number.

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 in 11 ways as a sum of consecutive naturals, for example, 1303426 + ... + 1463553.

Almost surely, 2^221535406656 is an apocalyptic number.

It is an amenable number.

221535406656 is an abundant number, since it is smaller than the sum of its proper divisors (418024350544).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221535406656 is a wasteful number, since it uses less digits than its factorization.

221535406656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2767136 (or 2767123 counting only the distinct ones).

The product of its (nonzero) digits is 1296000, while the sum is 45.

The spelling of 221535406656 in words is "two hundred twenty-one billion, five hundred thirty-five million, four hundred six thousand, six hundred fifty-six".