221121001001 has 4 divisors (see below), whose sum is σ = 221292546900. Its totient is φ = 220949455104.

The previous prime is 221121000973. The next prime is 221121001021. The reversal of 221121001001 is 100100121122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 169291925401 + 51829075600 = 411451^2 + 227660^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221121001001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221121001021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85771016 + ... + 85773593.

It is an arithmetic number, because the mean of its divisors is an integer number (55323136725).

Almost surely, 2^221121001001 is an apocalyptic number.

It is an amenable number.

221121001001 is a deficient number, since it is larger than the sum of its proper divisors (171545899).

221121001001 is a wasteful number, since it uses less digits than its factorization.

221121001001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171545898.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 221121001001 its reverse (100100121122), we get a palindrome (321221122123).

The spelling of 221121001001 in words is "two hundred twenty-one billion, one hundred twenty-one million, one thousand, one".