221000001 has 16 divisors (see below), whose sum is σ = 318561600. Its totient is φ = 135805248.

The previous prime is 220999997. The next prime is 221000027. The reversal of 221000001 is 100000122.

It is a happy number.

It is not a de Polignac number, because 221000001 - 2² = 220999997 is a prime.

It is not an unprimeable number, because it can be changed into a prime (221000071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50286 + ... + 54503.

It is an arithmetic number, because the mean of its divisors is an integer number (19910100).

Almost surely, 2^221000001 is an apocalyptic number.

It is an amenable number.

221000001 is a deficient number, since it is larger than the sum of its proper divisors (97561599).

221000001 is a wasteful number, since it uses less digits than its factorization.

221000001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104848.

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 221000001 is about 14866.0687809521. The cubic root of 221000001 is about 604.5943605132.

Adding to 221000001 its reverse (100000122), we get a palindrome (321000123).

It can be divided in two parts, 22 and 1000001, that multiplied together give a palindrome (22000022).

The spelling of 221000001 in words is "two hundred twenty-one million, one", and thus it is an aban number.