221009591 has 16 divisors (see below), whose sum is σ = 244297728. Its totient is φ = 198273600.

The previous prime is 221009567. The next prime is 221009603. The reversal of 221009591 is 195900122.

It is not a de Polignac number, because 221009591 - 2¹⁴ = 220993207 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 (221009521) 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, 392276 + ... + 392838.

It is an arithmetic number, because the mean of its divisors is an integer number (15268608).

Almost surely, 2^221009591 is an apocalyptic number.

221009591 is a deficient number, since it is larger than the sum of its proper divisors (23288137).

221009591 is a wasteful number, since it uses less digits than its factorization.

221009591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 982.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 221009591 is about 14866.3913240571. The cubic root of 221009591 is about 604.6031055750.

The spelling of 221009591 in words is "two hundred twenty-one million, nine thousand, five hundred ninety-one".