221031091 has 4 divisors (see below), whose sum is σ = 222142000. Its totient is φ = 219920184.

The previous prime is 221031089. The next prime is 221031101. The reversal of 221031091 is 190130122.

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 221031091 - 2¹ = 221031089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221031001) 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, 555156 + ... + 555553.

It is an arithmetic number, because the mean of its divisors is an integer number (55535500).

Almost surely, 2^221031091 is an apocalyptic number.

221031091 is a deficient number, since it is larger than the sum of its proper divisors (1110909).

221031091 is a wasteful number, since it uses less digits than its factorization.

221031091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1110908.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 221031091 is about 14867.1144140348. The cubic root of 221031091 is about 604.6227103732.

The spelling of 221031091 in words is "two hundred twenty-one million, thirty-one thousand, ninety-one".