221310220320021 has 64 divisors (see below), whose sum is σ = 344714140108800. Its totient is φ = 123690223742976.

The previous prime is 221310220320019. The next prime is 221310220320031. The reversal of 221310220320021 is 120023022013122.

It is not a de Polignac number, because 221310220320021 - 2¹ = 221310220320019 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 221310220320021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221310220320031) 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 63 ways as a sum of consecutive naturals, for example, 358470426 + ... + 359087268.

It is an arithmetic number, because the mean of its divisors is an integer number (5386158439200).

Almost surely, 2^{221310220320021} is an apocalyptic number.

221310220320021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

221310220320021 is a deficient number, since it is larger than the sum of its proper divisors (123403919788779).

221310220320021 is a wasteful number, since it uses less digits than its factorization.

221310220320021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 619018.

The product of its (nonzero) digits is 576, while the sum is 21.

Adding to 221310220320021 its reverse (120023022013122), we get a palindrome (341333242333143).

The spelling of 221310220320021 in words is "two hundred twenty-one trillion, three hundred ten billion, two hundred twenty million, three hundred twenty thousand, twenty-one".