221091071 has 4 divisors (see below), whose sum is σ = 221311200. Its totient is φ = 220870944.

The previous prime is 221091053. The next prime is 221091127. The reversal of 221091071 is 170190122.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221091071 - 2¹⁴ = 221074687 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221091371) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108551 + ... + 110568.

It is an arithmetic number, because the mean of its divisors is an integer number (55327800).

Almost surely, 2^221091071 is an apocalyptic number.

221091071 is a deficient number, since it is larger than the sum of its proper divisors (220129).

221091071 is a wasteful number, since it uses less digits than its factorization.

221091071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220128.

The product of its (nonzero) digits is 252, while the sum is 23.

The square root of 221091071 is about 14869.1314810247. The cubic root of 221091071 is about 604.6773964811.

The spelling of 221091071 in words is "two hundred twenty-one million, ninety-one thousand, seventy-one".