221101001 has 24 divisors (see below), whose sum is σ = 258552000. Its totient is φ = 188508320.

The previous prime is 221100989. The next prime is 221101007. The reversal of 221101001 is 100101122.

It is a de Polignac number, because none of the positive numbers 2^k-221101001 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221101001.

It is not an unprimeable number, because it can be changed into a prime (221101007) 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 23 ways as a sum of consecutive naturals, for example, 146750 + ... + 148248.

It is an arithmetic number, because the mean of its divisors is an integer number (10773000).

Almost surely, 2^221101001 is an apocalyptic number.

It is an amenable number.

221101001 is a deficient number, since it is larger than the sum of its proper divisors (37450999).

221101001 is a wasteful number, since it uses less digits than its factorization.

221101001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1597 (or 1586 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 221101001 is about 14869.4653905243. The cubic root of 221101001 is about 604.6864490956.

Adding to 221101001 its reverse (100101122), we get a palindrome (321202123).

It can be divided in two parts, 221 and 101001, that multiplied together give a triangular number (22321221 = T₆₆₈₁).

The spelling of 221101001 in words is "two hundred twenty-one million, one hundred one thousand, one".