221191001 has 4 divisors (see below), whose sum is σ = 221233152. Its totient is φ = 221148852.

The previous prime is 221190979. The next prime is 221191049. The reversal of 221191001 is 100191122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221191001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221191051) 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, 11861 + ... + 24146.

It is an arithmetic number, because the mean of its divisors is an integer number (55308288).

Almost surely, 2^221191001 is an apocalyptic number.

It is an amenable number.

221191001 is a deficient number, since it is larger than the sum of its proper divisors (42151).

221191001 is an equidigital number, since it uses as much as digits as its factorization.

221191001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42150.

The product of its (nonzero) digits is 36, while the sum is 17.

The square root of 221191001 is about 14872.4914187234. The cubic root of 221191001 is about 604.7684846022.

The spelling of 221191001 in words is "two hundred twenty-one million, one hundred ninety-one thousand, one".