221520091 has 8 divisors (see below), whose sum is σ = 238758464. Its totient is φ = 204310080.

The previous prime is 221520077. The next prime is 221520113. The reversal of 221520091 is 190025122.

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

It is not a de Polignac number, because 221520091 - 2²⁷ = 87302363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221520001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10831 + ... + 23671.

It is an arithmetic number, because the mean of its divisors is an integer number (29844808).

Almost surely, 2^221520091 is an apocalyptic number.

221520091 is a deficient number, since it is larger than the sum of its proper divisors (17238373).

221520091 is a wasteful number, since it uses less digits than its factorization.

221520091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14181.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 221520091 is about 14883.5510211777. The cubic root of 221520091 is about 605.0682626798.

The spelling of 221520091 in words is "two hundred twenty-one million, five hundred twenty thousand, ninety-one".