221021100021 has 16 divisors (see below), whose sum is σ = 294915091328. Its totient is φ = 147237307200.

The previous prime is 221021100011. The next prime is 221021100073. The reversal of 221021100021 is 120001120122.

It is not a de Polignac number, because 221021100021 - 2¹⁹ = 221020575733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221021100011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34418391 + ... + 34424811.

It is an arithmetic number, because the mean of its divisors is an integer number (18432193208).

Almost surely, 2^221021100021 is an apocalyptic number.

It is an amenable number.

221021100021 is a deficient number, since it is larger than the sum of its proper divisors (73893991307).

221021100021 is a wasteful number, since it uses less digits than its factorization.

221021100021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13212.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 221021100021 its reverse (120001120122), we get a palindrome (341022220143).

The spelling of 221021100021 in words is "two hundred twenty-one billion, twenty-one million, one hundred thousand, twenty-one".