221001221020021 has 32 divisors (see below), whose sum is σ = 244016304537600. Its totient is φ = 198908710392000.

The previous prime is 221001221020009. The next prime is 221001221020061. The reversal of 221001221020021 is 120020122100122.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 221001221020021 - 2¹⁹ = 221001220495733 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221001221019977 and 221001221020004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221001221020061) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 43609980 + ... + 48413146.

It is an arithmetic number, because the mean of its divisors is an integer number (7625509516800).

Almost surely, 2^{221001221020021} is an apocalyptic number.

It is an amenable number.

221001221020021 is a deficient number, since it is larger than the sum of its proper divisors (23015083517579).

221001221020021 is a wasteful number, since it uses less digits than its factorization.

221001221020021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4803729.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 221001221020021 its reverse (120020122100122), we get a palindrome (341021343120143).

The spelling of 221001221020021 in words is "two hundred twenty-one trillion, one billion, two hundred twenty-one million, twenty thousand, twenty-one".