221055561 has 20 divisors (see below), whose sum is σ = 337903632. Its totient is φ = 143940888.

The previous prime is 221055533. The next prime is 221055577. The reversal of 221055561 is 165550122.

221055561 is a `hidden beast` number, since 2 + 2 + 105 + 556 + 1 = 666.

It is not a de Polignac number, because 221055561 - 2⁹ = 221055049 is a prime.

It is a super-2 number, since 2×221055561² = 97731122098049442, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (221055511) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 28251 + ... + 35216.

Almost surely, 2^221055561 is an apocalyptic number.

It is an amenable number.

221055561 is a deficient number, since it is larger than the sum of its proper divisors (116848071).

221055561 is an equidigital number, since it uses as much as digits as its factorization.

221055561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63522 (or 63513 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The square root of 221055561 is about 14867.9373485363. The cubic root of 221055561 is about 604.6450218223.

The spelling of 221055561 in words is "two hundred twenty-one million, fifty-five thousand, five hundred sixty-one".