221996591 has 8 divisors (see below), whose sum is σ = 240789024. Its totient is φ = 203841280.

The previous prime is 221996569. The next prime is 221996609. The reversal of 221996591 is 195699122.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 221996591 - 2¹⁴ = 221980207 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 (221996521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 158555 + ... + 159948.

It is an arithmetic number, because the mean of its divisors is an integer number (30098628).

Almost surely, 2^221996591 is an apocalyptic number.

221996591 is a deficient number, since it is larger than the sum of its proper divisors (18792433).

221996591 is a wasteful number, since it uses less digits than its factorization.

221996591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318561.

The product of its digits is 87480, while the sum is 44.

The square root of 221996591 is about 14899.5500267626. The cubic root of 221996591 is about 605.5017952866.

The spelling of 221996591 in words is "two hundred twenty-one million, nine hundred ninety-six thousand, five hundred ninety-one".