221661355 has 16 divisors (see below), whose sum is σ = 277355520. Its totient is φ = 169852032.

The previous prime is 221661343. The next prime is 221661359. The reversal of 221661355 is 553166122.

221661355 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 221661355 - 2²⁷ = 87443627 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221661359) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12397 + ... + 24433.

It is an arithmetic number, because the mean of its divisors is an integer number (17334720).

Almost surely, 2^221661355 is an apocalyptic number.

221661355 is a deficient number, since it is larger than the sum of its proper divisors (55694165).

221661355 is a wasteful number, since it uses less digits than its factorization.

221661355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12198.

The product of its digits is 10800, while the sum is 31.

The square root of 221661355 is about 14888.2959065166. The cubic root of 221661355 is about 605.1968532741.

The spelling of 221661355 in words is "two hundred twenty-one million, six hundred sixty-one thousand, three hundred fifty-five".