221001221021 has 4 divisors (see below), whose sum is σ = 252572824032. Its totient is φ = 189429618012.

The previous prime is 221001220981. The next prime is 221001221039. The reversal of 221001221021 is 120122100122.

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 not a de Polignac number, because 221001221021 - 2¹⁰ = 221001219997 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221001220987 and 221001221005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221001221041) 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, 15785801495 + ... + 15785801508.

It is an arithmetic number, because the mean of its divisors is an integer number (63143206008).

Almost surely, 2^221001221021 is an apocalyptic number.

It is an amenable number.

221001221021 is a deficient number, since it is larger than the sum of its proper divisors (31571603011).

221001221021 is an equidigital number, since it uses as much as digits as its factorization.

221001221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31571603010.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 221001221021 its reverse (120122100122), we get a palindrome (341123321143).

The spelling of 221001221021 in words is "two hundred twenty-one billion, one million, two hundred twenty-one thousand, twenty-one".