221666001764520 has 128 divisors (see below), whose sum is σ = 665751281207040. Its totient is φ = 59043997347840.

The previous prime is 221666001764509. The next prime is 221666001764563. The reversal of 221666001764520 is 25467100666122.

It is a super-3 number, since 3×221666001764520³ (a number of 44 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 221666001764520.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 675521290 + ... + 675849350.

It is an arithmetic number, because the mean of its divisors is an integer number (5201181884430).

Almost surely, 2^{221666001764520} is an apocalyptic number.

221666001764520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221666001764520 is an abundant number, since it is smaller than the sum of its proper divisors (444085279442520).

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

221666001764520 is a wasteful number, since it uses less digits than its factorization.

221666001764520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334435 (or 334431 counting only the distinct ones).

The product of its (nonzero) digits is 1451520, while the sum is 48.

The spelling of 221666001764520 in words is "two hundred twenty-one trillion, six hundred sixty-six billion, one million, seven hundred sixty-four thousand, five hundred twenty".